Yep, this side-gilled slug looks like a yellow or orange gumdrop — albeit a good sized one. The ones with bumps on their overtly gelatinous bodies make them look a lot like sea lemons or oranges.  I have seen them as large as 2 1/4″ or 60 mm.  These seem to be relatively common — at least in the liminal zone near tidepools,  in lagoons and surgy, protected areas.  According to Cory Pittman and Pauline Fiene, my go-to experts, they are known to have a varied diet of sponges and different species of coral.