Another critter has materialised. How?

[Mrty]

I've had a few different critters appear recently, and not so recently, but now despite not introducing anything new to the tank since May last year I've got a new one appeared.
Looking at it, it appears to be a brittle starfish. Fascinating to watch it move round the tank, is actually pretty fast, do they breed by splitting or does it takes two to tanko?
Also, where has it come from? I can't have missed it for 10 months surely. I've got a great macro video but can't share it on here, so here's a couple of stills.

 

[ISpeakForTheSeas]

I've had a few different critters appear recently, and not so recently, but now despite not introducing anything new to the tank since May last year I've got a new one appeared.
Looking at it, it appears to be a brittle starfish. Fascinating to watch it move round the tank, is actually pretty fast, do they breed by splitting or does it takes two to tanko?
Also, where has it come from? I can't have missed it for 10 months surely. I've got a great macro video but can't share it on here, so here's a couple of stills.

They can reproduce fissiparously (by splitting into two), so in this case it doesn't necessarily take two to tango, no. If you haven't added anything, then it has been winning in a very long game of hide and seek - it had to have come into the system on something you added, and it has likely been hiding in the rocks/sand this whole time.

(Some people have reported breaking down tanks that have been running for years only to discover new creatures they never knew were in the system hiding there once they tore everything down, so this may happen more often than one would think.)

 

[Soren]

I've had a few different critters appear recently, and not so recently, but now despite not introducing anything new to the tank since May last year I've got a new one appeared.
Looking at it, it appears to be a brittle starfish. Fascinating to watch it move round the tank, is actually pretty fast, do they breed by splitting or does it takes two to tanko?
Also, where has it come from? I can't have missed it for 10 months surely. I've got a great macro video but can't share it on here, so here's a couple of stills.

That looks like a micro-brittle starfish. I was hoping for some with my ocean live rock last March and did not see them until just a couple weeks ago even though I was specifically watching for them! They do hide well.

 

[elm03]

I've had a few different critters appear recently, and not so recently, but now despite not introducing anything new to the tank since May last year I've got a new one appeared.
Looking at it, it appears to be a brittle starfish. Fascinating to watch it move round the tank, is actually pretty fast, do they breed by splitting or does it takes two to tanko?
Also, where has it come from? I can't have missed it for 10 months surely. I've got a great macro video but can't share it on here, so here's a couple of stills.

No idea what that is but it’s kinda scary looking lol

 

[Mrty]

Thanks guys. Guess I'll cancel my call to the Pope reporting a new 'immaculate conception'. As 'ELM' says, it is kinda scary looking. Looked to me like a tiny robot, with the perfectly circular body and the weird looking joined legs. Looks even weirder in the video . . . *cue H G Wells War of the Worlds*