I'm going to kill my friend's aloe vera on purpose because she doesn't care that her cat keeps getting upset stomach from eating it
Why would you kill the plant though?
The cat throws up on my floor quite often after eating her aloe vera.
It's nice that you care for the cat. Instead of destroying aloe vera you should tell your friend about it. You can't destroy her plant.
It's more damage to the friendship than someone throwing up. I don't want to tell her.
I really think that sitting down and talking to her about the cat will resolve the issue here.