Anyone know what this is growing on my snail? It's only on this guy who obviously is now named Einstein. It doesn't seem to be causing any issues, just curious.
Looks like colonial hydroids. They can sting corals if they bump corals, but corals generally win a growth contest and smother them. Technically a pest for the stinging ability, but a very minor one, and cool-looking.
Nice snail decor. Keep it. Neat that they're bigger near the big end of the shell.