I hope this teacher has a good sense of humor, otherwise these kids probably got subjected to all of the pop quizzes for this.
The kids put an air horn underneath their teacher's desk so that when he sat down, the horn went off and scared the daylights out of him. If my experiences in school and playing pranks is any indication, this could easily backfire on them so I certainly hope that the laughs were worth it.
Photo Credit: Getty Images