My understanding was it’s bad practice to host images on Lemmy instances anyway as it contributes to storage bloat. Instead of coming up with a one-off script solution (albeit a good effort), wouldn’t it make sense to offload the scanning to a third party like imgur or catbox who would already be doing that and just link images into Lemmy? If nothing else wouldn’t that limit liability on the instance admins?
Gluttony might be an interesting idea. It’s not necessarily necromantic, but the idea of using magic to force a person to eat until they cannot continue and literally rupture.
Or, and this probably sounds stupid, but you could have a modified form of the grease spell that’s just wet noodles. I don’t know if you’ve ever stepped/slipped on wet noodles, but it’s disgusting and traumatic.