Can Someone Identify What This Is?

[shizzle24]

We bought some live rock and this thing was on it. I've had various stores say different things. Can anyone tell me what it is?? The picture is from when we first got it.

Then if you know what it is, can you explain what it's doing below? I noticed yesterday it was ballooning out....

 

[HiddenUser]

Some sort of Rock Anemone?

 

[Tahoe61]

Looks like a Fire Anemone type.

 

[6dxb9aph]

Its a rock anemone