Ms. Bitters with Crazy Card.
A Crazy Card is a small card at the Skool used to send any student who is deemed insane to the Crazy House. Each classroom receives three Crazy Cards a month.
In "Halloween Spectacular of Spooky Doom", Zita uses a Crazy Card to send Dib to an insane asylum, known as the Crazy House For Boys. Once a Crazy Card is used, a device called a Crazy Collar is put on the crazy person's neck. Then, a team of specialists will burst into the Skool, throw the crazy child into the back of their van, and take them to the Crazy House.
If the child is thought to be crazy by scientists, they will be imprisoned for as long as the rest of their life. Each class only gets 3 crazy cards a month - that is 36 cards a year, or 30 cards a school year, as a school year tends to only be as long as 10 months.