The phrase identifies attire intended for the Halloween holiday that is inspired by the characters from the Alvin and the Chipmunks franchise. This encompasses outfits that resemble Alvin, Simon, Theodore, and sometimes other characters from the animated series and films. An example includes a red sweater with a yellow “A” for Alvin, along with corresponding chipmunk features like ears and a tail.
The popularity of such ensembles stems from the enduring appeal of the characters, particularly among children and families. Wearing such an outfit provides a recognizable and lighthearted option for Halloween celebrations. These outfits offer a nostalgic reference for adults who grew up with the franchise, while also providing an engaging option for younger generations who are familiar with more recent iterations of the characters.