Nutty

Nutty was a dog that was owned by Frank Heffley, that was mentioned in Diary of a Wimpy Kid: Dog Days. Frank stated that Nutty was his dog when he was a child, but ran into a butterfly farm, and never saw him since. After Frank tells his story, Greg's Grandpa stated that he accidentally ran over Nutty with a vehicle, assuming it was his skateboard, and made up the butterfly farm story to cover up what really happened.

Since Frank's father made the lie of Nutty running away to a butterfly farm, Frank never knew about what really happened to Nutty until one Father's Day. He turns very pumped up, then replacing Nutty with Sweetie with a smile on his face.

In the online book, Nutty was a cat. Nutty wasn't hit by a car; he was left outside and froze to death.