It?s a busy time in Room 2B?an ant observation project is beginning, Miss Mackle is teaching square dancing, and class pictures are being taken. Then one of the fish from the 2B fish tank goes belly-up! Is Harry to blame?

It?s a busy time in Room 2B?an ant observation project is beginning, Miss Mackle is teaching square dancing, and class pictures are being taken. Then one of the fish from the 2B fish tank goes belly-up! Is Harry to blame?

Doug discovers that though being Harry's best friend in Miss Mackle's second grade class isn't always easy, as Harry likes to do horrible things, it is often a lot of fun.

Harry leads a mission to place cobwebs all over school, shows the class how to make green slime, and stages a "deadly skit" that has everyone on the edge of their seats.

Horrible Harry has always loved insects, especially digging in the dirt for them. And, recently, he's discovered a new favorite: earwigs! But when he tries to tell his friends about these critters, only Song Lee listens. So when Miss Mackle assigns groups in Room 3B to act out different fairy tales, Harry sees an opportunity to teach the class about his favorite bug. Will they think his play is hilarious...or horrible?

Harry's in love, and his best friend, Doug, is disgusted -- Harry won't even throw snowballs at girls anymore. Will Harry ever go back to being his horrible self?"Kline captures perfectly the crowd scenes and private moments in the classroom."-- Booklist