"T" shaped inverts?

[R2Dork]

I've seen a little T-shaped guy in my tank a handful of times, and always assumed he was a starfish hitchhiker that had a rough life and lost a couple of arms. BUT today I saw two of them, and they both only have 3 arms! That can't be a coincidence, right? What the heck are these?

Here's a pretty good picture of one (sorry, didn't have time to put the filter on my phone):



Here's a not-as-good pic of both of them. The first one is upper right and the other is lower left:



Thanks for looking!
 

[WV Reefer]

6 minutes ago, R2Dork said:

I've seen a little T-shaped guy in my tank a handful of times, and always assumed he was a starfish hitchhiker that had a rough life and lost a couple of arms. BUT today I saw two of them, and they both only have 3 arms! That can't be a coincidence, right? What the heck are these?

Here's a pretty good picture of one (sorry, didn't have time to put the filter on my phone):



Here's a not-as-good pic of both of them. The first one is upper right and the other is lower left:



Thanks for looking!
 

Asterina starfish. 

[hinnenkm]

It's an asterina star - one way they reproduce is by fission (splitting themselves in half). This is the reason you're only seeing part of one. Most are harmless, but keep an eye on them because I've had some that liked to eat my zoas.

[R2Dork]

Thanks friends! I thought it was a starfish with missing arms, but seeing two of them with the same exact shape threw me off. 😊

And thanks for the warning... I'll definitely be keeping an eye on them.