is this a baby sea hare? or cucumber?

[Cheeser]

found it on my glass the other day.

 

[bjohanson1234]

Looks like a type of nudibranch. What kind, I could not say.

 

[Bifferwine]

It is not a seahare or cucumber. It is a nudibranch, most of which are predators on a certain type of coral. I would remove it.

 

[Smitty]

+1 Bj and Biff.