Spoiler-Itis is an episode of the ALVINNN!!! and The Chipmunks series.
As Brittany walks by the school lockers wearing a new shirt, Theodore compliments her but Alvin gives a snarky remark. The Chipmunks and The Chipettes discuss their plans to watch the season finale of Alien Cat Invasion and that they don't want Alvin to spoil it for them. To prove that he has self control to not spoil shows, Alvin accepts a bet in which he must not speak for 24 hours starting at midnight. If Alvin loses, he has to wear Brittany's shirt for an entire day, but if he wins, he gets to be carried around school while the others chant "Alvin rules" and feed him Yummy Bunnies. That night, Alvin stays up watching Alien Cat Invasion and tries to wake up Simon to tell him about it, but before he can, Simon's alarm clock strikes midnight and the bet begins. Alvin later has a nightmare that he is in a basement talking to a bunch of cats about the episode while the others are spying on him using a microphone collar on Shirley. The Chipettes rush through the door to catch Alvin for talking and he is forced to wear Brittany's shirt. The next day Alvin goes through many events of his normal day that are made more difficult and miserable because he isn't allowed to speak. Alvin ends up in detention for doing an oral report as a mime, and Dave gets upset as he and Miss Smith demand an explanation for Alvin's behavior but don't get a response. Alvin escapes the classroom and catches up with his brothers and the girls, who continue to mock him for struggling to resist talking. Back at home, all of them start to watch the already recorded season finale of Alien Cat Invasion when Theodore accidentally sits on the remote and erases the show. Desperate to know what happened in the show, Alvin is begged from the others to tell them, but he uses the opportunity to get back at them by giving them the silent treatment, winning the bet. The following day Alvin gets carried around school by Simon and The Chipettes while being fed Yummy Bunnies by Theodore as they all chant "Alvin rules."
- "Hush, Hush" 
- Alvin dressed as a mime could be a throwback to the season one episode My Sister The Weirdo.
- When this episode premiered in the US, it aired with a re-run of Addicted.