Hypnokat is the 7th episode of Season One. After Kat sabotaged Coop's skateboard jump, Coop locks Kat out of the house all night as revenge. While outside, Kat becomes the leader of a group of friendly stray cats when they meow along with him. He tries to train them to attack Coop viciously, but fails because the cats all rub against the scarecrow of Coop lovingly instead. After being brought back inside, Kat is given a toy mouse by Dad from the House of Swap , and it hypnotizes him until he gets splashed in the face with water. Kat decides to use the hypnotic mouse to hypnotize his cat army into viciously attacking Coop.
Later, Coop gets chased as he zooms past Lorne and Harley and they run over all strached up. He pursued into Dennis' house by the army of vicious cats after being locked out of his own house. Coop and Dennis work together to defeat the cat army. They eventually figure out that they can break the cats' hypnosis by spraying them with water, and the cats turn against Kat after they snap out of it. As revenge, Coop uses the hypnotic mouse on Kat in the end. But instead of using the hypnotic mouse to make Kat nice to him and keeping it forever, Coop just uses it to make Kat dance like a ballerina with Millie. Granted, if Coop used the mouse to make Kat always nice to him, it might end the series (and Kat might have destroyed the mouse as soon as he could anyways), but it was still quite jarring that Coop never used the mouse to his advantage that way. We see a toy mouse that looks identical to the hypnotic mouse in later episodes, but it no longer hypnotizes any cats. Coop goes off to make his jump again with Dennis and takes the mouse with them now that Kat's hypnotised again.