The sarcastic fringehead fish is one ferocious, territorial motherfucker. I had never heard of a sarcastic fringehead before and after watching this video, I’m not too sure I ever want to again.

According to Wikipedia:

When two fringeheads have a territorial battle, they wrestle by pressing their distended mouths against each other, as if they were kissing. This allows them to determine which is the larger fish, which establishes dominance.

 
I watched the whole video through. But if you want to get to the horror, it starts at the 2:09 mark.

 
Via JWZ