When you get explosive diarrhea from eating at the shacks at Ross Univeristy.
Jess: I can't go out tonight, i'm having a shack attack.
Rob: Happens to everyone, next time just buy a banana haha.
the act of blowing up someone's spot when they have a shacker still in their presence. Usually results in an embarassing incident.
My parents totally shack attacked me when they arrived early for lunch and my shacker was walking out the front door.