Moray

When an eel has a maw with a pharyngeal jaw, that's a moray.
When the jaws open wide and there's more jaws inside, that's a moray
When it sulks in a reef and has two sets of teeth, that's a moray.
When an eel bites your thigh and you bleed out and die that's a moray

Moray eels have a second set of jaws. Their pharyngeal jaws, hidden in their throat, shoot forward to grab prey and pull it deeper into their mouths just like in Alien.