Dog Days is an episode of the ALVINNN!!! and The Chipmunks series.
Theodore is watching Alvin practice a trick at the skate park when one of his wheels rolls into a box. Theodore goes to retrieve it only to find a puppy which he attempts to hide from Alvin. Back at the Seville House, Alvin tries to convince Simon to help them keep the puppy from Dave, but he isn't convinced they're responsible enough to have a pet. While Theodore uses puppy talk on him, Dave arrives to tell them of his cousin's new baby. They quickly eat dinner and look at a picture of the new baby before rushing back to the puppy now named TJ. The next day when Dave's out gift shopping The Chipmunks play with the dog. The puppy sneaks out of their room leaving an unpleasant surprise for Dave to step in. To take one for the team, Alvin says it was Theodore. Despite attempts to keep TJ in their room, he keeps getting out and rips up the couch, gets in the trash, digs up the flowers, steals Dave's slipper, and leaves more messes for Dave. Alvin and Simon argue to Dave that Theodore's behavior is the result of Theo being replaced as the baby. Miss Croner finds out about Theodore's supposed pooping problem and sorts him out by using a litter box and treats. They see a missing poster for the puppy so Theodore reluctantly returns him. Miss Croner learns from Dave that the problem is solved and she agrees to do the same for Alvin if he becomes a problem. In their room, Alvin overhears Miss Corner speaking to Dave about sending him to her house and "getting his tail on straight," to which Alvin yells "NO!"
- This episode is a nod to The Alvin Show episode Theodore's Dog and The Chipmunks episode Three Chipmunks and a Puppy.
- A sneak-peek clip was released on Nick.com.
- When this episode premiered in the US, it aired with a rerun of Mutiny.