Any thought on these chaetomorpha critters?

[glendale789]

Found these in my @AlgaeBarn chaeto added last month. I also added new frags from @OSA a few days ago...

UPDATE:
Stomatellas.
Thanks @Bob Loblaw!
Also a great critters thread compliments of @Crabs McJones

 

[El_Guapo13]

I was going to say flatworm, but looks to round and fat. Maybe a slug of some sort?
#reefsquad

 

[El_Guapo13]

I was going to say flatworm, but looks to round and fat. Maybe a slug of some sort?
#reefsquad

Maybe one of these?

Account Suspended

 

[Bob Loblaw]

Stomatellas, beneficial cuc.

 

[El_Guapo13]

Stomatellas, beneficial cuc.

Oh wow. I couldn't even tell they had a shell. Nice catch.

 

[glendale789]

Maybe one of these?

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Thanks @El_Guapo13. They do look similar, but these do have a shell which is hard to see. I think @Bob Loblaw is correct. I found more pics on Melevsreef.com

 

[glendale789]

Stomatellas, beneficial cuc.

Awesome! That’s it! They’re my first “pests” and it’s great to know they are beneficial and reef safe. More on melevsreef.