Murphydoris cf. cobbi
This is an incredibly tiny nudibranch (3-4 mm max), so tiny that I thought it was more likely that I was taking a photo of a shell . . . until it moved and disappeared quickly into a hole. There are a few clearer photos of this on the Sea Slugs of Hawaii site. Cory Pittman states that there have only been three individuals found, the first one being as recent as October, 2022. This would make it four individuals documented. This little one was found in less than 2 metres of water in the North Kihei area of Maui — 2mm?