snail algea

I purchased a few more snails for clean up crew on my 25 gallon tank that is roughly a year and a half old. I don’t recognize the growth on its shell, can anyone identify it? Should I be concerned? It almost looks like small spikes sticking out of the top surface of its shell.

Hello everyone! I have a question on one of my Margarita snails there appears to be a hole with this funky plant looking think growing out of the shell. Is this something anyone can identify and does it hurt the snail/will it spread beyond the shell or to new snails? Appreciate any help!

Just got a CUC yesterday - saw this in one of the snails, can you ID and let me know if action is needed, thanks everyone