Strange mollusc type animal

[just_oli]

Hello,

Im kinda new to the aquarium hobby, having my saltwater tank for about 8 months now, and I noticed this mollusk type animal on my glass.
Could anyone tell me if it’s a parasite or just a new addition to my tank?

Any help would be appreciated thank you

 

[KrisReef]

Shape looks like a Chiton of some sort?

 

[Steve and his Animals]

Probably just small limpets, very common type of snail that multiply well and clean well.