What is this id please

[Mtwreef]

Spotted this on one of my rocks not sure what it is now there is a spider web looking thing coming out of it any help please it's in the middle that's as far as I could zoom into it

 

[RalphsReef]

Looks like a spaghetti worm. Harmless.

 

[a49panhead]

looks like a Vermetid snail. they dont hurt much but spread quick. crush it at the bass with a pir of tweezers to kill it. there r some natural predators like a mystery wrasse that will help control them.