The meanest thing my friend did to a sub?

my silly friend was trying to make coffee in the class and so called accidentally pour sugar in the sub's hair. it was weird but yet funny. then when she got suspended it wasn't funny at all. i don't think it was an accident i think it was suppose to be a joke but she screamed accident! it was mean because she was a nice teacher she really didn't disturbed to be respected! even though thinking of that moment was sort of hilarious!!!