Help ID this critter

[eagerreefer]

Trying to figure out what this is. They are in my sump as well as all over some of my rocks. They kind of look flatworm shaped but stand straight out on the rock. Thanks!

 

[xxkenny90xx]

Pineapple sponges? Can you get a close up pic?

 

[vetteguy53081]

Looks like filter feeding pineapple sponges

 

[El_Guapo13]

Agreed. Pineapple sponges.

 

[SHNICI]

If they look/are a bit fluffy then it's filter feeding pineapple sponges like the others says (Harmless for your tank)