Bite mark on monti cap?

[Calgoby]

Anyone ever heard of a pincushion urchin munching on monti cap? Thoughts on whether it could be monti nudibranchs?

It looks like the skeleton got chewed on and not just soft tissue - the edge was previously convex so a decent piece (4x2mm) of coral got bitten off.

The urchin refuses to eat nori or dry kelp (grrrr....)

 

[Kremis]

probably not the urchin, what else do you have? looks close to the rock, maybe urchin just moved it and it got scraped?

 

[thesassyindian]

That looks a lot like a coral sting rather than a bite.
Do you have any corals with sweepers close by? eg. Galaxea, Favia, etc?

What are these two corals?

 

[JVU]

Urchins certainly can much SPS by accident as they try to eat adjacent algae. I wouldn’t worry about it if that’s the case, since they aren’t targeting it and it’ll grow back fast.

Does not look like monti-eating nudibranch injury at all to me.