Domino and sea urchin behavior

[New hobbyist]

My domino and my sea urchin seem to have made some type of relationship. The domino almost looks like he's trying to host in the spiney sea urchin. Which seems really odd to me. He backs up carefully into the spines of the urchin and the urchin just sort of pushes the domino back and forth with his spines. Is this normal? I've seen them do this several times.

[Sniperhank]

Not any behavior that I'm aware of, but doesn't mean that it isn't a thing.

[New hobbyist]

Crazy! Thank you

[Andy Sager]

Domino damsels are one of the ones that will go into anemones same as clownfish so the wanting to go into the urchin is not that unusual. Second part, there are a few types of fish ( ie some cardinal species, minnows) that purposely use long spine urchins for protection when young so again, the action is not that unusual. Some cardinals even use the urchins to release their young into them and won't release without them present.