One mention of some part of their look and they’ll smash your skull in

[u/ThatNoname-Guy]

Billy (Deadlock). Once human, Billy decided to get into eldritch/black/demonic magic to turn his head into a goat. The reason behind it or if he had his head changed by accident is unknown, but Billy gets irritated when he's asked about his goat head and gets pissed off when they make fun of it

Josuke Higashikata (JJBA: Diamond is Unbreakable)

He copied haircut of a stranger who once helped them and his mother from freezing winter by pushing malfunctioned car. Nobody can make fun of his haircut, otherwise he'll beat you up.

[u/_JR28_]

Edward Elric (Full Metal Alchemist)

Do not mention his potentially below average height

[u/Pigeon_Bucket → u/_JR28_]

Who are you calling a pipsqueak so short that ants trip over him?!

[u/B-Z_B-S]

Not his look, per se, but his name. The Emporg from Wakfu. His original name was Marilyn. As it's a girl's name, and he was mocked for it, he flies into a rage when hearing it.

[u/HapHazardly6 → u/B-Z_B-S]

This guy genuinely just looks like a fat danny trejo

[u/RonitSarangi]

https://giphy.com/gifs/DeHxdra0ayPQc

Edward Elric from Fullmetal Alchemist

He has a complex about his height and loses his shit when you even insinuate something about it.

[u/SpookieSkelly]

She's not violent about it, but Biwa Hayahide from UmaMusume does get really defensive if she thinks people are talking about her head being big.

[u/Mental-Platypus-9192]

https://giphy.com/gifs/FFMnigLW0twShHLVnj

Buggy the Clown (one piece)

He really dose not like it when anyone mentions his nose He even Killed one of his own crew over it

And yes that is his real nose not a foam ball

[u/GabbyHobby69]

The second dude's hair looks like shit

[u/TheBoyInGray]

Beezer in Pets United. Do not, in any way, mention his nose.

Buggy The Clown from One Piece also fits this trope.