polyclad flatworm snail or coral eater?

[JoJosReef]

Found this guy last night. I've been losing a bunch of nerites lately and even a couple of ceriths and an astraea. Thought it might be an unidentified hitchhiker crab or eunice worm(s), but now I'm wondering if it could be this guy.

Any thoughts? Likelihood of a bunch more in the tank? Evo 13.5g with 3 gulf live nano rocks.

 

[Rick's Reviews]

Looks like a Nassarius snail or dove snail, unsure about green stuff growing over/binding but definitely does not look good, anything else unusual in aquarium

Following

 

[WheatToast]

Looks like a Nassarius snail or dove snail, unsure about green stuff growing over/binding but definitely does not look good, anything else unusual in aquarium

Following

I am not seeing any shell on the organism, so my guess would be a flatworm and not a snail. From what I have read, they will consume mollusks, but they have never infested my tank.

 

[Rick's Reviews]

This looked to me like a snail being eaten by green slime, I have outlined what I thought was shape... Being consumed by green stuff, did not mean it's a snail lol. I Meant it used to be what appears to be a snail being devoured by green stuff

 

[JoJosReef]

This looked to me like a snail being eaten by green slime, I have outlined what I thought was shape... Being consumed by green stuff, did not mean it's a snail lol. I Meant it used to be what appears to be a snail being devoured by green stuff

Good eye, but the thing actually looked very much like the picture @WheatToast posted. In this picture, the worm kind of folded over on itself, hence the darkish part of it that could be mistake for a shell (def no shell).

 

[Mhamilton0911]

Looks like a leopard polyclad flatworm, totally a killer of snails and even hermit crabs of it can catch one. I lost several snails and I finally caught mine when it was devouring my Halloween hermit crab. Nasty little bugger.