What is this? (Hitchhiker id)

[rsigler]

Hey Gang,

I've seen this little guy in my display, and now in my sump. In the display, it looked like it had orange spikes on it's back. It seems to have two antennas like some sort of slug or snail.

Is it reef safe? Should I keep him? It's about the size of your pinky nail.

:) Rob

 

[rsigler]

And here he is in my display under blue lights...sorry for the crappy photo. Seems to have a bubble on it's back.

 

[stylaster]

nudibrach of some sort. Most are predators, i would take him out