Pack Animal is an episode of the ALVINNN!!! and The Chipmunks series.
When Dave tells Simon to get rid of some stuff, a few of his most dangerous inventions end up in the wrong hands. 
Dave opens the living room closet and ends up on the floor as a mound of boxes fall on him. He instantly believes Alvin is to blame, ordering him to clean it up, until Simon admits he's at fault. While Alvin waits for an apology from Dave, Simon explains the mess is spare parts from past inventions with no where else to go. When Dave is once again knocked down by more of Simon's inventions in the basement, Simon agrees to get rid of everything. Alvin learns Simon wasn't punished and can even keep the important pieces so he confronts Dave about the double standard in the Seville House when it comes to punishments. Simon spends most of the evening sorting through the pieces, ultimately separating out his dangerous inventions. Exhausted, Simon falls asleep waking to Theodore holding breakfast and learning he took the wrong box to the buy and sell shop. The pair rush to the shop learning all of the stuff sold already. With the assistance of The Chipettes, Simon and Theo follow the mayhem around town to collect the various inventions Simon intended to keep out of others' hands. Meanwhile Alvin lectures Dave about how to be a fair father, desperate for a proper apology. Hearing Simon outside, he checks on him learning Simon's most dangerous device, capable of creating a black hole, is missing. Theodore points out the black hole forming over the Humphrey's residence and find Neville playing with the device, sucking up things until they too are sucked in. With a little team work, they are able to escape. Dave finds Alvin in the basement later to apologize until he's buried with stuff Alvin brought back.
- "Get Yourself Together" 
- Goof: Dave says his printer is out of paper but he takes out the ink cartridge instead of refilling it with more paper.
- Several of Simon's inventions and other machines from previous episodes make reappearances. Such as the jet pack from A Is For Alien, the brainwave machine from Held Back, the Mega-Magnet from Overlooked, the teleportation ray orb from Wacky Wednesday, the ping-pong robot from Lucky Day, and the shrink ray from Queen Bee. Additionally, the satellite dish that would later be used in Across the Universe makes an appearance.
- A sneak peek clip was released to Nicktoons UK.