According to Jim: Season 1, Episode 3 - ProjectFreeTV

1 - 3: The Cat Came Back

Cheryl's 15 year-old cat Mr. Feeney dies and she wants Jim to bury it on the backyard, but Jim wants to go to the Bears game with Dana and Andy. He sticks the cat in the garage freezer, planning on burying it after the game, but Cheryl finds out before he comes home.