1) Fish 
The hammerjaw, Omosudis lowii, is a small deep-sea aulopiform fish, found worldwide in tropical and temperate waters to 4,000 m (13,000 ft) depth. It is the only representative of its family, Omosudidae (from the Greek omo, `shoulder`, and Latin sudis, either `esox, fish of the Rhine` or `stake`). The large head is dominated by a massive, tr...