This is the Sarcastic Fringehead. It's angry. Really angry. This is what happens when someone actually does blow their top.
They reach 30 cm (12 in) in length and while they still live in crevices and discarded shells, they're keen to leap out and scare the bejesus out of anything that encroaches on their territory.
This is when their special face is deployed. The ridiculously long maxilla bones in the upper jaw are extended outward to ensure their mouth can get just as grotesque as possible. If the cause of all this is another Sarcastic Fringehead, it will probably be doing exactly the same thing. It's their way of saying "hello, I'm sooooo pleased to meet you" *rolls eyes*.
If one of the rivals doesn't back down in horror at the sheer size of the other guy's gape (or the sudden realisation that they must look just like that), then passive aggression gives way to a face-fight as terrible mouth meets terrible mouth. Their faces are locked in combat like two naked and completely heterosexual Greek wrestlers.
Other creatures, including humans, receive the same treatment. If you're something that wasn't there when they last looked, you're in trouble. And if the face doesn't work, then the needle-like teeth are next. Some people use sarcasm as a kind of defence or attack. The Sarcastic Fringehead just uses its actual mouth. Which is sort of ironic.
|Image: Ken Bondy via Flickr|
All in all the Sarcastic Fringehead doesn't seem to be sarcastic at all. Then you might consider that "sarcastic" comes from a word that literally meant "to strip flesh", just as sarcophagus literally means "flesh-eating". I think whoever named this thing had a smile on his face. When it comes to wit, sarcasm isn't all bad.