Hey Paul...
I know you've got a lot of years of experience, but don't you think you've got that hammer a little close to that coral to the right... think it's a hairy mushroom, or a leather? Hammers can wipe things out pretty quick if you're not careful.
Foundnemo11... that's not normal, for sure. In the 2nd picture, on the head that's just above the deflated head, it looks like a small portion of that head doesn't look good either - the part of it that's closest to the deflated head. Could something have fallen on that head? Maybe some salt crust from a tank lid? Or a snail from above? Maybe a piece of that birdsnest above it broke off and fell into it? Just talking out loud...