What is this? Anemone?

[GMeWu99]

I had my tank running for about a year. This thing was around 1/4 of an inch big at first and now has grown to be around 2 inches almost 2 1/2 inches wide. Can anyone identify this?

 

[Smo]

Looks like a very nice mushroom to me!
On the other hand, I could be wrong.

 

[Fluff]

Looks like a fuzzy mushroom.

 

[Scatcat]

Ditto although I saw some frog spawn that looked like that but it's much more bushy. Probably a mushroom.

 

[spongeynip]

Frogspawn also looks more shiny, bubbly, and thicker. I thought it was that at first too, but the smaller, flatter structure shows its inner mushroom

 

[lando]

Fuzzy mushroom