His Brain Has A Virus

(I am a system administrator in a high school. One of the computers in a lab is currently disconnected from the network and I have taped a sign on it until I get a chance to repair it. I am working on a computer nearby.)

Sign: “This computer has a virus. Please do not plug into network.”

Teacher: *reads sign, then plugs in network cable and turns on computer*

Me: “What did you do that for?”

Teacher: “I… don’t know.”