what kind of mushroom is this?

[jlee22]

This mushroom just pop up in my tank one day I dont know what kind it is

[inthedeep2]

a nice one. better then the green ones I had pop up on me.. lol

[bobo33]

Nice color

[Nanook]

[moved]

[organism]

Looks like a Discosoma with what may be a brown flatworm on it.

[reefer999]

+1 to above, looks like a flatworm, I would suggest getting rid of them.