How to prevent passive buff placers from working on certain units?
I'm doing a slight variation of Abaddon's Curse of Avernus (abaddon_frostmourne), where he can apply several stacks of the curse. The skill is done (attached at the end of the post), but I couldn't prevent it from working on towers - this was problematic, as it became too strong this way (creeps on maximum speed attacking a super-slowed-down tower is pretty fun, but you quickly figure its broken).
I looked around and messed with the ability's targetting, but didn't manage to overcome this. I would like the passive to work on all regular units (enemy heroes + creeps, neutrals) but not on structures. Can anyone help find a way?
Thank you very much!
I'm copying the skill's current implementation below: