Critter on my torch

[JasonCG]

Can anyone help me ID these critters on my torch? There’s at least 2, and they’re large and have a hard shell. They retract against the coral when I try to grab them with forceps. My guess is that they’re flatworms, but I always thought they’d be squishy, and not hard like these guys. I assume that whatever they are, the treatment will be the same, but any pointers would be appreciated!

 

[Mr Cypher]

can't tell from pics do they have feelers?

 

[vetteguy53081]

Left side - unwelcomed nudibranch and right looks like poriferan sponge
Removed the both and discard

 

[Mr Cypher]

hm

 

[JasonCG]

can't tell from pics do they have feelers?

Maybe very tiny feelers, very short and skinny. Here’s a slightly better picture.