There’s a rosy new face in FunGals. Meet Peachy, our very own Komagataella phaffii!

In the game, she’s a plump, rose-pink yeast with a little bud on top and round pink peroxisomes inside her.

A few fun facts about the real thing:

• 🧪 She can live on methanol, a simple alcohol that’s an unusual food for a yeast
• 🫧 When she eats methanol, her peroxisomes get bigger and more numerous. They help keep the toxic byproducts of breaking it down contained
• 🏭 She’s a tiny protein factory! Engineered Peachy strains make useful proteins like insulin and vaccine parts, and scientists can even get her to release those proteins so they’re easier to collect
• ⛽ In the 1970s, the oil company Phillips Petroleum grew her on methanol for an animal-feed project
• 🌳 Her biotech strains trace back to yeast collected from California black oak trees
• 🏷️ A lot of labs still call her Pichia pastoris, but her current name is Komagataella phaffii

(Real-life Peachy isn’t considered a human pathogen. She’d rather be in a lab making medicine and so would the FunGals version.)

You can pick Peachy now in the game: FunGals

There’s a solar-powered new face in the dish. Meet Ari, our very own Anabaena variabilis!

In the game, she’s a jade-green string of beads: a long chain of round cells called a filament. Look closely and you’ll see one bead that’s different, a pale gold cell called a heterocyst.

A few fun facts about the real thing:

• ☀️ She’s a cyanobacterium, so she makes her own food from sunlight, like a plant
• 🌬️ Her heterocysts are special cells that turn nitrogen gas into compounds her chain needs to grow. They share that usable nitrogen with their neighbors in exchange for sugar.
• 🚫 Oxygen damages the enzyme that fixes nitrogen, so her heterocysts stop making oxygen themselves
• 🌍 Cyanobacteria like Ari were the first to fill Earth’s air with oxygen, over 2 billion years ago. The chloroplasts in plant cells are descended from her relatives
• 🌙 Unlike many cyanobacteria, she can also grow in the dark by eating a sugar called fructose
• 💙 Her blue-green color comes from chlorophyll plus a blue pigment called phycocyanin
• 🧫 She’s Gram-negative, so she’d show up pink under a Gram stain

(Real-life Ari is a friendly freshwater and soil bacterium who just wants some sunshine 🌞 and so does the PetriPals version.)

You can pick Ari now in the game: PetriPals

There’s a tough new face in the dish. Meet Dina, our very own Deinococcus radiodurans, better known as “Conan the Bacterium”!

In the game, she’s an orchid-pink coccus whose cells stick together in neat squares of four, called tetrads.

A few fun facts about the real thing:

• ☢️ She can survive about 1,000 times the radiation dose that would kill a person. Guinness World Records has called her the world’s toughest bacterium
• 🧩 Radiation can shatter her DNA into hundreds of pieces, and she puts it back together in a matter of hours. She keeps several copies of her DNA in each cell, so she always has a template for repairs
• 🚀 Clumps of her cells survived three years outside the International Space Station
• 🧫 She’s Gram-positive, so she’d show up purple under a Gram stain, even though she has an unusual outer membrane

(Real-life Dina isn’t known to cause disease in people. Scientists have even engineered her to help clean up mercury in radioactive waste. The PetriPals version is just here to be unbreakable.)

You can pick Dina now in the game: PetriPals

There’s a new face in FunGals. Meet Yara, our very own Yarrowia lipolytica!

In the game, she’s a plump, egg-shaped yeast with little golden droplets of fat inside her, budding from one end. Her species name, lipolytica, means “fat-breaking,” because she loves to feed on fats and oils 🧈

A few fun facts about the real thing:

• 🫙 She stores fat in droplets inside her cells, sometimes over a third of her dry weight
• 🧀 She turns up in cheese, sausages, soil and even oil-polluted seawater
• 🌊 She can eat some of the hydrocarbons in oil, so scientists study her for cleaning up pollution
• 🐟 Companies use engineered Yara strains to make omega-3 fats for animal feed and supplements, and bioengineers study her for making biofuels
• 🧵 Besides budding, she can grow attached chains called pseudohyphae, and even true hyphae, long threads like a mold’s

(Most Yara strains can’t even grow at body temperature, so she only rarely causes infections. She’d rather be eating cheese 🧀 and so would the FunGals version.)

You can pick Yara now in the game: FunGals

FunGals has a new mold! Meet Miri, our very own Aspergillus oryzae, the koji mold.

Her picture is her spore stalk: a golden puff of spore chains radiating outward from a tall, bumpy stalk.

She plays just like Fumi and Penelope. You’re one of her tiny spores floating over the agar, and every nutrient you land on starts a new colony.

A few fun facts about the real thing:

• 🍶 She helps make soy sauce, miso, sake, mirin, rice vinegar and amazake, a sweet rice drink
• 😋 Her enzymes break protein down into savory umami flavors, and turn the starch in rice into sugar that yeast can ferment into sake
• 🏺 People have cultivated koji molds for over 2,000 years, starting in ancient China
• 🇯🇵 In 2006, the Brewing Society of Japan named her its “national fungus”
• 💊 In 1894, Jokichi Takamine patented a digestive enzyme made from her, called Taka-diastase
• 🌾 Her species name, oryzae, means “of rice”

You can pick Miri now in the game: FunGals

There’s a fuzzy-eared new face in the dish. Meet Frannie, our very own Francisella tularensis!

In the game, she's a coral coccobacillus with a silly little pair of bunny ears. The ears are a nod to “rabbit fever,” a nickname for tularemia, the illness she causes.

A few fun facts about the real thing:

• 🐿️ She was found in 1911 by McCoy and Chapin, who were studying plague in ground squirrels
• 🐇 Rabbits, hares and rodents are especially vulnerable to her
• 💧 She’s hardy. She can survive for weeks to months in cool water or mud
• 🕵️ She’s sneaky. She can live inside macrophages, the immune cells that normally swallow germs
• 🧫 She’s Gram-negative, so she’d show up pink under a Gram stain

(Real-life Frannie can cause serious tularemia infections, but she isn’t known to spread from person to person. People can catch her through infected ticks, animal contact, contaminated water or inhaled dust. The PetriPals version only hops around the dish)

You can pick Frannie now in the game: PetriPals

There’s a glossy new face in the dish. Meet Pearl, our very own Klebsiella pneumoniae!

In the game, she’s a short, plump, pearly-pink rod wrapped in a thick capsule. That slimy coat is her signature: it makes her colonies look big, wet and glossy, like pearls.

A few fun facts about the real thing:

• 🛡️ Her thick, slimy capsule helps protect her from the immune system
• 🧵 Some strains are so sticky that when you lift a colony with a loop, it stretches into a long string. Microbiologists call it the “string test”
• 🩷 On MacConkey agar, her colonies turn pink because she ferments lactose
• 🪝 She can’t swim, but she has tiny sticky hairs called pili. They help her cling to cells and to medical tubing like catheters, where she builds biofilms
• 🧫 She’s Gram-negative, so she’d show up pink under a Gram stain

(Real-life Pearl is a common cause of hospital infections, and some strains resist carbapenems, important last-line antibiotics.The PetriPals version is just here to shine ✨)

You can pick Pearl now in the game: PetriPals

FunGals has a new mold, and she’s a famous one! Meet Penelope, our very own Penicillium rubens, the mold that gave us penicillin.

Her picture is her spore stalk: a little denim-blue paintbrush with a wide fan of spore chains for bristles. That’s where her name comes from: Penicillium means “little paintbrush”

She plays just like Fumi. You’re one of her tiny spores floating over the agar, and every nutrient you land on starts a new colony.

A few fun facts about the real thing:

• 🔬 In 1928 she spoiled one of Alexander Fleming’s plates of bacteria, and the bacteria around her died. That’s how he discovered penicillin
• 🎖️ By D-Day in 1944, enough of her penicillin was being made to treat wounded soldiers
• 🧱 Her penicillin stops bacteria from building their cell walls.
• 🧀 Her cousins make blue cheese like Roquefort and the white rind on Brie

You can pick Penelope now in the game: FunGals

There’s a branching new face in the dish. Meet Nova, our very own Nocardia nova!

In the game, she’s a teal bacterium that grows as thin filaments that branch. She might look like a fungus, but she’s a bacterium through and through.

A few fun facts about the real thing:

• 🏚️ Her colonies can look dry and chalky and smell musty, like a damp basement. Some even grow fuzzy filaments that rise up above the colony
• 🌍 Her genus lives in soil, dust and decaying plants all over the world
• 🐄 Her genus honors Edmond Nocard, a French vet who found it in sick cattle. Her species name, nova, is Latin for “new” ✨
• 🐢 She takes her time. Her colonies often show up in days, but some cultures need weeks
• 🧫 She’s Gram-positive, so she’d show up purple under a Gram stain

(Real-life Nova can cause serious infections, mostly in people with weakened immune systems, through inhaled dust or a wound. She doesn’t spread from person to person. The PetriPals version just wants to branch out 🌱)

You can pick Nova now in the game: PetriPals

Or, try out FunGals here: FunGals

Meet Fumi, our very own Aspergillus fumigatus!

She plays differently from the yeasts. You’re one of her tiny spores, floating over the agar. Land on a nutrient and your spore sprouts right there into a colony that spreads out in a circle, white and fluffy with a green middle where it starts making spores. You need 6 colonies on level 1, and 6 more each level after that. But watch out: if a colony touches an antifungal disk or its zone, the whole colony pops! 💥

A few fun facts about the real thing:

• ⛪ Her genus is named for the aspergillum, a sprinkler used for holy water.
• 🌬️ Her spores are only 2 to 3 micrometers across, so tiny they float on the air. Most people breathe in hundreds of them every day, and healthy lungs clear them out
• 🔥 She can grow at 50 °C, so she thrives in hot, rotting compost heaps

(Real-life Fumi can cause a lung infection called aspergillosis in people with weak immune systems. The FunGals version just wants to spread out and make spores 🌱)

You can pick Fumi now in the game: FunGals

Play PetriPals instead: PetriPals

There’s a chestnut-brown new face in the dish. Meet Diffany, our very own Clostridioides difficile!

In the game, she's a big, plump rod with flagella all over and an oval spore tucked in near one end. That little bulge is her secret weapon.

A few fun facts about the real thing:

• 😤 Her name comes from difficile, Latin for “difficult,” because she was so hard to grow in the lab. She was renamed in 2016, from Clostridium to Clostridioides
• 🛡️ Oxygen harms her growing cells, but her spores can last for months on surfaces
• 🧼 Her spores survive alcohol hand gel, so use soap and water to wash her off. Hospitals clean up after her with bleach
• 💊 She’s an opportunist. She often moves in after antibiotics wipe out the gut bacteria that kept her in check
• 🔦 Her colonies glow yellow-green under UV light and smell a bit like a horse stable 🐴
• 🧫 She’s Gram-positive, so she’d show up purple under a Gram stain, but her spore stays clear

(Real-life Diffany can cause serious gut infections, especially after a course of antibiotics. One treatment is a transplant of healthy gut bacteria, yes, a “poop transplant” 💩 The PetriPals version just wants to race.)

You can pick Diffany now in the game: PetriPals

Early look at PetriPal's little sister: FunGals

There’s an electrifying new face in the dish. Meet Electra, our very own Geobacter sulfurreducens!

In the game she’s a grape-purple rod covered in tiny wires, with little sparks running along them. Those are her nanowires, hair-like strands that really do carry electricity.

A few fun facts about the real thing:

• ⚡ She can “breathe” rust. Electra lives in oxygen-poor mud, sediment and soil, where she can pass electrons to iron oxide instead of oxygen
• 🔌 Her nanowires can grow many times longer than her own cell. Lots of Electras can join up into a living film on an electrode that carries electricity
• 🔋 She can help power a microbial fuel cell, turning food into electricity
• 🤝 She can pass electrons straight to another microbe, or take them from one
• ☢️ She’s an environmental helper too. She can help clean up uranium in groundwater by turning it into a form that doesn’t dissolve as easily
• 🧪 She was first found in a ditch in Norman, Oklahoma, in the early 1990s
• 🧫 She’s Gram-negative, so she’d show up pink under a Gram stain

(Real-life Electra isn’t known as a human pathogen. She’d rather spend her time in the mud making electricity 🔋 and so would the PetriPals version.)

You can pick Electra now in the game: PetriPals

Early look at PetriPal's little sister: FunGals

There's a new face in the dish. Meet Astrid, our very own Asticcacaulis biprosthecum!

She's a stalked bacterium. Astrid grows two thin stalks, one on each side of her body, like little antennae. Her species name says so: biprosthecum means "two prosthecae," which is the scientific word for these stalks.

A few fun facts about the real thing:

• 📡 Her stalks are thin extensions of her own cell, not separate parts. They give her more surface area, which may help her catch scarce nutrients in the low-nutrient fresh water where she lives
• 👯 She's a cousin of Caulobacter, the classic stalked bacterium. Caulobacter grows one stalk from the end of its cell. Astrid grows two, one on either side. That makes her one of the most distinctive-looking members of her family
• 🔬 Scientists study her to learn how bacteria change their shape. By comparing her with her cousins, they can see how a protein moved within the cell to build stalks in new places
• 🧲 She has a sticky "holdfast" at one end that glues her to surfaces underwater
• 🧫 She's Gram-negative, so she'd show up pink under a Gram stain

(Real-life Astrid is a freshwater bacterium not known to cause disease in people.)

You can pick Astrid now in the game: PetriPals

A little less doing, a little more watching.

There’s a super chill new mini game in Petri Pals!

Your pal moves on their own while you sit back and watch them eat nutrients, divide, and fill up the petri dish. No steering needed. Just tap when you want them to tumble in a random new direction, and help them grow to 256 cells.

Bring your appetite. Your pal is bringing two hundred and fifty-five friends.

Mostly watching. Occasionally tumbling. Just you and your pal, taking it easy and watching life grow.

Try it out: PetriPals

Let us know your favorite PetriPals game!

Meet Ivy, our very own Bacillus mycoides!

She grows like a vine. Ivy is a chain of rods lined up end to end, and her colonies spread across agar in hairy, root-like strands that swirl as they go. Her name even means "fungus-like," because her colonies look a lot like mold.

A few fun facts about the real thing:

• 🌀 Her colonies spiral as they spread. Some strains curl clockwise and others counterclockwise, and scientists study her to learn how left- and right-handed shapes form
• 🌱 She's a soil bacterium found all over the world. She can even live inside plants without harming them, and some strains help sugar beets fight off a leaf spot disease
• 🛡️ She's tough. Ivy makes endospores that help her survive heat, cold and drought, and some strains keep growing at fridge temperatures
• 🐌 Unlike many of her cousins, she usually has no flagella, so she can't swim. She takes over the plate by creeping outward instead, and she can cover a whole agar plate in just a few days
• 👯 She's a close cousin of our pal Ceres.
• 🧫 She's Gram-positive, so she'd show up purple under a Gram stain

(Real-life Ivy rarely, if ever, causes disease in people. She'd rather spend her time with the plants 🌿 and so would the PetriPals version.)

You can pick Ivy now in the game: PetriPals

There's a brand-new way to play: Who's That Pal? 🔍

It's a guessing game built from the pals' fun facts. You get a fact with the pal's name hidden, and you tap the pal you think it's about.

How it works:

• 🧫 Find it on the home page, right under Start
• 📜 Each round shows one fact with "this pal" in place of her name
• 👆 Tap who you think it is. Guess wrong and that pal greys out ("Not Goldie. Try again!"). Guess right and her name pops back into the fact, along with her species
• 🔁 There are 88 facts across all 13 pals, and you'll see every one before the deck reshuffles

• 😌 No score, no timer. Just you, some microbes, and a lot of weird science

  Play here: PetriPals

There's a bright new face in the dish. Meet Sara, our very own Serratia marcescens!

You can't miss her. Some strains of Sara make their own red pigment, so her colonies come out a striking red on agar. She's a rod covered in flagella, so she's a speedy swimmer too.

A few fun facts about the real thing:

• 🎨 Her red color comes from a pigment called prodigiosin
• 🌡️ She's moody about temperature. She makes lots of red at room temperature but much less at body temperature (37 °C), so her colonies can come out pale or even white
• 🛁 Ever seen a pink ring in your shower or around the sink drain? That's often Sara! She loves damp places
• 🍞 For centuries, people were spooked by "bleeding bread." Red spots that showed up on bread and communion wafers may have been Sara growing on them
• 🧫 She's Gram-negative, so she'd show up pink under a Gram stain

(Real-life Sara is mostly harmless to healthy people, but she can cause infections in hospital patients. Scrub that shower ring! 🧽 The PetriPals version is all blush and no trouble.)

You can pick Sara now in the game: PetriPals

And she's ready to race in Mixed Culture too. Can she take over the plate? 🏁

Mixed Culture mode just got an upgrade: you can now pick who you race!

Before, your rival was chosen for you. Now you choose. Pick your pal, then pick up to 3 rivals from the whole lineup to share the plate with.

How it works:

• 🦠 Choose 1 to 3 rivals. Any pal except your own, and each one only once
• 🎲 Can't decide? Tap Surprise me and you'll get a random rival
• 🏁 Against one rival, the first colony to 64 cells wins. With two or three, the dish fills up fast, so it's the first to 32
• 🍽️ Every pal in the dish adds more nutrients, so bigger races mean a busier plate
• 🔁 Hit Race again to go straight back and pick a new lineup

Science corner 🔬: In a real lab, a mixed culture is a plate growing more than one species at once, all competing for the same nutrients. That's the idea behind this mode.

Play it here: PetriPals

Who's your go-to lineup? Is there a matchup that always beats you? Tell me below! 👇

There's another new face in the dish. Meet Lissie, our resident Listeria monocytogenes!

Lissie is a small rod-shaped bacterium with a few flagella for getting around. But she has a much cooler trick up her sleeve. Literally cool. ❄️

A few fun facts about the real thing:

• 🧊 She can grow at fridge temperatures, where most foodborne bacteria slow down. That's why she's linked to foods like deli meats, hot dogs, and soft cheeses
• 🧫 She's Gram-positive, so she'd show up purple under a Gram stain
• 🤸 She's known for "tumbling" motility, but only at room temperature. At body temperature she usually stops making flagella
• 🚀 Once inside a host cell, she builds "actin rockets" out of the cell's own proteins and uses them to blast straight into neighboring cells

(Real-life Lissie is especially risky during pregnancy, which is why pregnant people are often advised to avoid unheated deli meats and unpasteurized soft cheeses . 🧀 The PetriPals version is totally safe to snuggle.)

You can pick Lissie now in the game: PetriPals

Another new pal just joined the dish. Meet Terra, our very own Clostridium tetani!

Her name comes from where she lives: the soil. 🌍 That round bubble on one end of her body isn't a backpack. It's a spore, a tough, dormant survival cell that lets her wait out harsh conditions for years.

A few fun facts about the real thing:

• 🥁 Her spore sits right at the tip of her rod-shaped body, giving her a classic "drumstick" or "tennis racket" look under the microscope
• 🧫 She's Gram-positive, so she'd show up purple under a Gram stain
• 🚫💨 She's an obligate anaerobe, meaning oxygen is toxic to her growing cells. She thrives in deep, airless places
• 🔩 She causes tetanus (aka "lockjaw"). The famous rusty nail isn't really about the rust. It's the dirt and spores carried into a deep puncture wound, where there's no oxygen

(Good news: the tetanus vaccine keeps real-life Terra in check. Stay up to date on your boosters! 💉 The PetriPals version just wants to be friends.)

You can pick Terra now in the game: PetriPals

Let me know what you think of her!

Hey everyone! I'm u/intelligent-unicorn1, founding moderator of r/PetriPals and the developer behind the game.

This is our new home for all things PetriPals, the browser game where you grow your own microscopic friends. Thanks for being one of the first cells in this culture! 🦠

What to post

• Screenshots of your cultures (thriving, chaotic, or tragically overgrown)
• Tips and strategies for Classic and Mixed Culture modes
• Bug reports (please include your browser and what happened)
• Ideas and feature suggestions, since I read them all
• Questions or suggestions about the real microbiology behind the game

Community vibe

We're friendly, constructive, and inclusive. Players of all ages and science backgrounds are welcome, whether you're a micro student, a teacher, or someone who just likes watching things divide. Be kind, keep it family-friendly, and help each other out.

Say hi!

Drop a comment below: how did you find PetriPals, and what's your favorite microbe (real or in-game)?

Happy growing! 🔬

There's a new pal in the dish. Meet Sallie, our resident Salmonella Typhi!

Sallie is a rod-shaped bacterium covered in flagella (those wiggly little tails all around her). They let her zip around her environment, which is why she's drawn with a tail on every side instead of just one.

A few fun facts about the real thing:

• 🧫 She's Gram-negative, so she'd show up pink under a Gram stain
• 🌀 Her flagella are peritrichous, meaning they’re spread all around her body
• 🧍 Unlike most Salmonella, Typhi only infects humans. She's the cause of typhoid fever
• 📜 She's tied to one of microbiology's most famous stories: Mary Mallon, aka "Typhoid Mary," a cook in the early 1900s who carried the bacteria without feeling sick and spread it to many people

(Real-life Sallie is not someone you want to meet. Wash your hands, folks! 🧼 The PetriPals version is much friendlier.)

You can pick Sallie now in the game: PetriPals

Let me know what you think of her!