Yeah, on my poor zoos.. Mine is the maned nudibranch. Apparently their diet is sea anemones, with a preference for the Frilled Anemone. I have none of those in my tank but you never know if they take a sudden liking to my zoos or mushrooms. Plus, I have two maned nudibranch in my tank and I guess those eggs must be theirs. And knowing that nudibranch are hermaphrodites, any two can lay more eggs..
Am now thinking of removing the nudibranch. One is stuck on the glass and another is in hiding.