Never seen that before. If they were eggs of nudibranchs they are much smaller. I would scrape them off and monitor them in a Tupperware container outside of the tank. See what they become
Oh boy that's scary to see. I have no clue what they at but I hope there nothing to crazy . Keep a watchfully eye out for your othe frags and rock work.
It's definitely some type of egg, but difficult to know what just by looking. My guess would be as kit Kat said, probably a fish based on how large they are.