While possessing with Dissolution all spells hit host instead
e.g. nimbus ray will hit the zombie you are possessing (and by extension, yourself). Not sure if intended. It kind of makes a cool interaction (by possessing a body you lose your holiness until you regain living flesh kind of feel) but it's probably a bug so I'll drop it here.
Most likely nothing I can do about it but link me the other mod so I can look into its source later.
https://github.com/Ladysnake/Dissolution I haven't poked too deeply into the code but from what I can see it simply assigns the spirit as riding the possessed entity? I haven't tried firing nimbus rays on horses yet actually, but I suspect something similar will result if you ride a large enough mob.