no idea-blue/black invert

Was doing some late night red light looking in my tank, which I love to do, I came across this guy who is new. The picture is horrible I know but once I put the light on him he had already started to go away so I had to be quick. From what I could see it was not a snail or crab. The “black” portion near his base was almost fuzzy looking and you can see he has some sort of antennae. From the picture is looks as if he was eating algae (looking at the green vs white on the rock and his placement). I put 99% dry rock in my tank so I have no idea where he could of come from. Any ideas? I’ll try to spot him again and get better pics. On a positive note, I did find my boxer crab(named Judo Chop) last night, thought he was gone after not seeing for 3 weeks.

 

looks like a margarita snail

 

Im guessing stomatella snail, but hard to say
Indo Pacific Snails

 

think your right cosmo

 

yea id say a trippy looking stomatella