When you place a pretend fishbowl on your friends head while they are having a marijuana trip. Then, you and other people around you proceed to have a conversation in silence by moving your lips and not talking. This causes the person in the fishbowl to think that they are actually in a fishbowl and start to freak out even more.
Joey: "We totally put Brad in the fishbowl yesterday. It was so awesome!"
Ryan: "Aw, man I can't believe I missed that! Did he trip?"