At first sight this is a fairly bland looking nudbranch as its cerata are a vague brown colour with spots (small papillae) and marks that match the seaweed or anemone food prey it is often found upon.  Look closely and it has beautiful yellow and white rings with a centre that is tinged a slight rosy-pink colour (though is can be missing in some individuals).  The number of spots in the centre of the rings can vary as well.  The Limenandra confusa is fairly similar looking but the papillae on its cerata and its markings are slightly different.  Most confusing is the fact that the confusa often has strong pink rings.  For more information, natural history, taxonomy, etc.,  see Sea Slugs of Hawaii.