Sea Hare and weird splitting backside

[JHEast]

I have a green algae eating Sea Hare and I know it's supposed to have those holes on it's back but why did it's back almost seem to split open at those holes? its still eating and moving around as it did before.

 

[footbagger311]

my sea hare got caught by a hairy red legged hermit and split his backside. luckily i found this happening before the little bunny got too injured. i had to separate the little bastard crab into the other tank.