What’s this creature in my QT

[accidental_reefer]

Hello. I’ve had a QT set up for 3-4 weeks with a piece of live rock and bunch of PVC. This translucent thing popped up from who knows where this weekend on the glass. First I thought it was a slug or a snail in search for a shell (since I’ve had cerith(?) babies appear in the last week for so. But then I piped some mysis and spirulina to feed the fish and then it turned into some tree-like shape. Anyone know what is this?

 

[ISpeakForTheSeas]

I’m struggling to tell exactly from the pics, but it looks like it may be an anemone of some kind. If so, most people would likely recommend removing it, as it may sting other tank inhabitants.

First I thought it was a slug or a snail in search for a shell

Snails grow their own shells, so a snail will never be in search of one.

 

[Spare time]

Kinda reminds me of a sea cucumber like creature.