Relatively Smaller (15-20 cm diameter) than carpet anemone
Laguna beach
These pics are all the same animal about 20 miles off of Monterey in 18C water. I am going backwards and forwards on whether it is a Northern or Guadalupe Fur Seal. It appears to have some fur on its front flippers.
There was no blue anywhere on this nudibranch, which led me, probably foolishly, away from the Cockscomb Nudibranch.