Help idk what this little guy is

[SaltLife4Life]

New to the hobby and clueless to things that just pop up in the tank

 

[Eagle_Steve]

New to the hobby and clueless to things that just pop up in the tank

Almost looks like a small monti eating nudibranch, well at least like the ones I had a few years ago come in on a monti frag. If it is, they eat more than montis.