ID for Florida Keys critter

I found two of these pretty unattractive creatures moving along the sandy bottom of a lagoon in the Florida Keys. It was about 2" long and plump, moved like a nudibranch but looked more like a sea hare. They weren't too far from a fueling dock, maybe they're mutations!

Would love to know what this little guy is.

Your on the money with Sea Hare, it's a Bursatella leachii.

Cheers,

Jim.