Wubbzy breaks Widget's whammer hammer by accident, but doesn't want to tell Widget. So Wubbzy makes up a story about a Growlygus stealing it, and it leads to chaos.
The episode begins with Wubbzy at Widget's workshop, with his kickety-kick ball. Widget decides to clean herself up, and leaves Wubbzy alone in the workshop. Even though he was told not to, Wubbzy started playing with his ball, and made a big mess in the process. Then to make things even worse, he broke Widgets whammer hammer when his ball banged onto it. When Widget comes back to find the mess, Wubbzy gets scared and starts lying about a Growlygus stealing her hammer. Widget then actually thinks that a Growlygus stole her hammer, and then told Wubbzy that they should find the monster to teach him a lesson. Wubbzy then realizes his mistake.
First, they go to Walden's house, where Walden starts looking on his computer for pictures of the Growlygus. However, he can't find any, so he asked Wubbzy to describe the monster to him. Wubbzy describes the monster as a really scary monster with lots of red fur and claws. However, he got really freaked out when he saw the picture that he described. Afterwards, he tries to make an excuse to go back to the workshop so he can fix Widget's whammer hammer, but Widget and Walden said that they needed to Wubbzy to come with them, since they think he is so brave.
While looking for the monster, they spot a police officer. They asked him if they have seen the Growlygus, but at first, the police officer says that he didn't. When he saw the picture that Walden drew, though, he freaks out. Word spreads around Wuzzleberg about the existence of the Growlygus, and Wubbzy feels more and more guilty in the process. Wubbzy then realize that he should tell Widget the truth. However, he is worried that if he does, then Widget wouldn't want to be Wubbzy's friend anymore.
While trying to search for the monster at Mt. Zubba Bubba, Wubbzy tries to find a way to scare widget and Walden away. That way, he could go back to Widget's workshop and fix her whammer hammer. After scaring Widget and Walden away face by growling and a cave, he hears growling and thinks it's the real Growlygus. He then starts to run away to warn Walden and Widget. However, the only thing that came out of the cave was a squirrel. Walden then asks Wubbzy what was going on. Wubbzy then confesses to Widget and Walden, saying how he wasn't brave after all. Widget then tells Wubbzy that he was brave all along, by telling the truth. She then says that they would always be friends no matter what.
At the end, Widget fixes her whammer Hammer. She then goes to start working on her newest invention, when Wubbzy starts saying that the Growlygus stole her hammer again. This time, he was telling the truth as the Growlygus is actually real. Scared, Wubbzy and Widget run away from him. He was left conflicted and said that he only wanted to borrow the hammer.
- News Reporter: Am I on? (clears his throat) It's pandemonium on the streets of downtown Wuzzleburg. Panic is-
- Police Officer: (runs by) The Growlygus is coming! The Growlygus is coming! (the reporter runs off screaming in a high pitched voice)
The song, "Don't Lie", is played.
Name in other languages
- Latin Spanish: Wubbzy dice una mentira
- German: Der unheimliche Grollozahn
- Spanish (Spain): Wubbzy cuenta una mentira
- Portuguese (Portugal): O Wubbzy diz uma mentira
- The computer at Walden's desk looks similar to the iMac G4.