Currently they spawn on the ground but then float upwards a bit, spawning them midair would be nice QoL to have for these mobs. This could also work really well for ghost rays in the End by having them spawn in the air between islands for some really nice ambience.

Like this?

Yeah that looks a lot better!

I'm still working on this. Most of them were spawned under the floating island. They'll need a spawn rule of "Y >= n" or something else sort of.