What’s this hitchhiker on the back of this Trocus snail? Looks like a double clam of sorts?

[HAWK44]

Noticed this on the back of my snail today while I was checking the tank out. Let me know what you think it is! I’m curious to know. Ignore the algae, I’m in a outbreak and trying to take control of it.

 

[Sharkbait19]

No pic attached.
Could be a bivalve, all sorts of things can come on snails.

 

[HAWK44]

I always forgot to upload the picture..

 

[Sharkbait19]

Definitely a bivalve of sorts. Does it open or close or is it stuck as is?

 

[HAWK44]

Literally reacts like a clam or muscle - closes quickly when you touch it and will reopen shortly after being left alone. This has been growing slowly by I have only recently noticed the mouth, if you will.
Edit: spelling.

 

[Sharkbait19]

Definitely a sort of bivalve then!
Neat hitchhiker!

 

[HAWK44]

Nice! Thanks!