Only comes out at night

[pseudorand]

I saw this guy for the first time looking at my tank after lights out tonight. Anyone have any idea? It's hard to see in the pic, but he has a bunch of tentacles flailing off of him.

 

[Ron Reefman]

I have never seen anything quite like that. Following.

#reefsquad

 

[ScottR]

Hard to tell without a clearer pic. My first thought is a polyclad flatworm

 

[fachatga]

Looks like some kind of slug to me.