ID please Critter on snail

[epicfatigue]

I noticed a odd looking guy in the bottom corner of the aquarium and I was like Ah wonder what that is then as a snail came past I noticed he had two on his shell as well.

Good bad any idea ?

They look like two other snails or scollops or something I duno

 

[KrisReef]

I believe those are a Crepidula.

There are also spirobids ( tiny white circles) and the tubes are either a feather worm or another Gastropod, maybe one of those net feeding nasty snails? I’m paused on the name of those and too tired to look it up. The tube snails are often considered as pests, if it has a calcium tube they can poke a nasty hole in a finger if you bump into them in the tank.

Sorry for the confusion I’m well done atm.