Snail has a friend

[CFerdman]

Hello! Could someone help me ID the creature living on my snail? Sometimes the shell opens away from the snail shell and little black antenna-like parts come out.

 

[Crabs McJones]

Crepidula fornicate, also known as the Slipper Limpet. Awesome hitchhiker

 

[CFerdman]

Crepidula fornicate, also known as the Slipper Limpet. Awesome hitchhiker

Thanks! Do you know if it bothers or causes pain to my snail?

 

[Crabs McJones]

Thanks! Do you know if it bothers or causes pain to my snail?

Nope. Basically latches into the snails shell and hitches a free ride and grazes on algae