Hitchhiker or Tumor on Ricordea?

[wineward]

A couple of days ago this "thing" started pushing up from beneath one of my shrooms. I cannot tell if it's a separate organism or simply a piece of aberrant tissue, like a tumor or impending reproduction. Does anyone recognize what's happening here?

In the close-up, it does appear to be a separate organism attached to the ceramic disc that has grown large enough to have started displacing the mushroom. Should I try to scrape it off the disc?

 

[JGT]

Could be bubble algae.

 

[Mr_Knightley]

Try and get a picture of it with the shrooms deflated, I can't see enough of it like this. It looks like a separate entity based on color, almost like a sponge or tunicate. Does it have any holes?

 

[wineward]

Try and get a picture of it with the shrooms deflated, I can't see enough of it like this. It looks like a separate entity based on color, almost like a sponge or tunicate. Does it have any holes?

I was thinking "tunicate" myself, but it is round instead of elongated like all or most tunicates. It does appear to have a siphon-like appendage, but no "holes."

Those mushrooms never deflate. Short of trying to push them away with some instrument, I'm not sure can get a better picture.

 

[wineward]

Could be bubble algae.

I don't think it is algae. It appears solid like coral tissue, or some filter feeder like a tunicate or tiny sea apple.

 

[ISpeakForTheSeas]

Yeah, I’d guess a tunicate as well. Their shapes actually vary pretty dramatically, so I wouldn’t discount it for being a bit oddly shaped. My guess is that if you look head on at the siphon-like appendage, then you’ll see it either is one hole or that it has two separate holes joined into it.

 

[Mr_Knightley]

I was thinking "tunicate" myself, but it is round instead of elongated like all or most tunicates. It does appear to have a siphon-like appendage, but no "holes."

Those mushrooms never deflate. Short of trying to push them away with some instrument, I'm not sure can get a better picture.

I still think it's a tunicate, they come in all sorts of shapes. As @ISpeakForTheSeas said, if it has another smaller siphon on the opposite side then it's most likely a tunicate. I can't imagine it doing any damage to the shrooms, so I say leave it.

 

[Fish Think Pink]

So, going with the tunicate answer and people saying leave it... if I were @wineward having it overgrow and displace my mushrooms, then I'd remove it.