Help identifying another critter please

[Mrty]

Found a tiny spot crawling up the wall of my tank. Expecting it to be a snail I zoomed in on my phone and found what looks like a hybrid of a jellyfish and an anemone. Though the 'jellyfish' is, I assume, the suction part of the 'animal'. Any ideas what it is and how big it will get please?

 

[Mrty]

Meant to say it's approx 4mm in diameter.

 

[ISpeakForTheSeas]

That looks like an anemone of some kind (the suction part being the foot). Not sure what kind or how big it'll get - sorry.

 

[Mrty]

That looks like an anemone of some kind (the suction part being the foot). Not sure what kind or how big it'll get - sorry.

Thanks, it's what I suspected. Moody of, because the tank is a 49 litres nano and now only soft corals and snails - which seem to tolerate the quick changes in water quality ( I will never have a nano again as you only need to eat a bacon sandwich in the same room and the nitrates go crazy). It's had no fish for months, no new corals for over a year, but new critters keep showing. Only things out in that tank for months is frozen food.

So far
half shell snails ( can't remember what they are called.
Brittle starfish ( nice but elusive)
Many tiny shrimp.
Tubeworm.
And now this anemone.
A total creationist dream.