What would u do to the guy who fungicide spray or mosquito spray at u? ...
Answers: You could sue him for assault with a lethal weapon Orrrrrrr...he he he...
Tell him you can do MUCH better than that!
Buy a pesticide fogger and tell him you are going to set it past its sell-by date in his room at hours of darkness in the immensely very practical future so he can breath within deadly pesticide for a few hours himself.
Then, even if you don't, you can hold the pleasure of knowing he'll be tossing and turning every time he hears any unusual sounds at hours of darkness.
If you REALLY want a fun harmless crow, buy some canned nouns or duster spray and when he is almost asleep spray it near his ear so that he think the fogger is going off.
put hot pepper liquid in his tooth mash or visene eye drops in his food