Mr. Sparks

Mr. Sparks was Greg's math teacher earlier in Greg's year. Every time he wanted his students, including Greg, to remember an important math concept, he stands on his chair. But one time, while he was standing on a chair, one of the chair's legs broke and he fell down. He broke his collarbone due to the fall.

Greg explains Mr. Spark in Cabin Fever on pages 29 and 30.