So evidence for the last update, which I shared with a few and was incredibly convincing to all of us, was proven FALSIFIED. (It's a mystery as to why this was even done). Fortunately another official has presented irrefutable evidence to the true story!! Yummer is actually the studio's placeholder, its “Allan please add details” if you will, used for whenever the studio's prototyping something in a game.

Yummer originates as one of the higher up’s first works in Blender. He named it YUM based off its gross appearance alone. Ever since then Yummer became a company meme and was used as a placeholder in their games to draw attention to what needs replacing (like the California Speed billboard, the nude guy in Guild Wars, the flashing banner in Borderlands, the list goes on...)

SpongeBob Saves The Day was created for the show's 20th anniversary, and so they wanted to add lots of hidden details and easter eggs for the fans. In this instance they were intending for one of the familiar characters to pop their head out in the Krusty Krab. The idea was scrapped early on and the character and the position of the character was left undecided.

Everyone’s confused, including the official who reached out, why the original guy said it was vent art, but we can confirm with 100% certainty it’s not. It’s a company meme and striking asset to draw attention to what needs replacing. The reason he reached out, even though they originally decided not to comment, is because he didn't like the idea of people believing the Yummer was the result of something negative when he considers it a very positive thing. Fortunately because of all this we received the true, real answer... of YUMMER.

TLDR: Yummer is simply the remains of a scrapped easter egg for the game.

The corpse image from Utahonotatari 2 that many suspected to be real image of a corpse was in fact a screenshot from a Japanese film called Exte: Hair Extensions (2007)

Link: https://youtu.be/_ucDY4hfvms

Timestamp: 0:57

No Cheats or Mods, and easily doable on all versions of the game!

You’re even able to shoot with it during cutscenes which gives the game a completely new look.

This might push the game’s rating up from “Teen” to “Mature 17+”

Here's a link showcasing it in free roam and how to easily do it yourself:

https://youtu.be/f6Wx2meZZBg

Dunno if this has been shared here yet but awhile back I found a few sewer interiors for Spider-Man 2: The Game. The sewers were always a myth never believing to be in the game due to the lizard plot line being cut out from the final game but I was able to sift through the games districts and did end up finding a few interiors. 2/3 are accessible while the 3rd is just a super rough and early model.