brown semi-soft body on live rock

[JoJosReef]

Seems to have a mouth. It is brown. Doesn't move from this spot. Appeared maybe a week or two ago. Tried wiggling it with forceps--has consistency of a dense sponge (kitchen, not animal) but doesn't come off the rock. Has what looks like a mouth that opens and closes occasionally. Any ideas? Thanks!

Open mouth:

Closed mouth:

 

[LegalReefer]

Probably a tunicate of some sort, harmless and even beneficial in some ways!

 

[leroytigerjohnson]

Agree, tunicate.

 

[Rtaylor]

Could be the siphon of a bivalve. Can’t tell from the pic. There are rock burrowing bivalves that you can only see the siphons. Typically you should see 2 close together if it is.

 

[Kyler P]

Agree with tunicate, when they contract their bodies can become very solid