These look like big, orange versions of the yellow nudibranchs known as "sea lemons". We call them sea oranges. I am not good at nudibranch identification but I will guess that it is one of the Dendrodorids. We found it on the urchin barrens, on the west side of Refugio Beach. It was about the size of a golf ball.
It's interesting how everything under water gets named after something above water. We have sea lemons, sea apples, seaweed, sea urchins, and now sea oranges and sea hedgehogs.
For though some old naturalists have maintained that all creatures of the land are of their kind in the sea; and though taking a broad general view of the thing, this may very well be; yet coming to specialties, where, for example, does the ocean furnish any fish that in disposition answers to the sagacious kindness of the dog? The accursed shark alone can in any generic respect be said to bear comparative analogy to him.
The labrador retriever of the sea is definitely the sheephead (which have nothing to do with sheep's heads, so far as I can tell). Sharks seem more like cats: maybe bobcats or cougars. Hermann should have learned to scuba dive.