Squid
Alternative names: Teuthida
Like cuttlefish, the Squid has eight arms that can regenerate and two longer tentacles that can't.
The squids that live in the depth of the water where there is no source of light have glowing organs which help them hunt for food. This means that you can see their lighted organs through their skin which makes them look like some kind of alien beings.
An interesting fact about the squid is that some of the species can produce an ink which contains high levels of dopamine which gives feelings of euphoria.