Odd protrusion from clam mantle

[pickupman66]

Anybody know what this may be? It's on a pretty happy derasa.
Dead center. Has 4 little dots. Looks like a polyp but it's part of the mantle.

 

[Shep]

Could just be some sort of harmless growth, @skinz78 might have a better idea

 

[skinz78]

It's part of the mantle.. LOL I have no clue

 

[NanaReefer]

Acne [emoji2]