Nut

A doctor at an insane asylum decided to take his patients to a baseball game. For weeks in advance, he coached his patients to respond to his commands.
When the day of the game arrived, everything seemed to be going well. When the National Anthem began, the doctor yelled, "Up nuts!" The patients complied by standing up.
After the anthem, the doctor yelled, "Down nuts!" so the patients all sat back down in their seats.
During the game, one of the players hit a home run. The doctor yelled, "Cheer nuts!" so the patients all broke out into applause and cheers.
Considering things were going very well, the doctor decided to leave his patients momentarily and get some munchies and a beer.
When the returned to his seat, there was a riot in progress.
"What happened?" he asked a fellow patron sitting next to his group.
The fellow replies, "Well... everything was going just fine until this guy walked by and yelled "Peanuts! Peanuts! Peanuts!"