ID help good or bad

[Gchen]

Hello guys I found that my live rocks have lots of this stuffs growing very fast even some growing on my frag. Some growing at the top of my GSP which made the GSP closed up. I am not sure what they are bad or good. Need some help thanks.

 

[jabberwock]

Maybe vermetid snail? Not great, can spread and sends out those snot strands. Not catastrophic, but I would crush it out of an abundance of caution.

 

[shakacuz]

it’s a vermetid snail. but you have what seems to be cyano as well (the red/purple stuff)