This episode was first for the 3rd season to be produced, but it changed air dates so that it could be shown on Christmas. Therefore, it's not chronologically first in Season 3 since the Season 2 finale, "The Big Brawl: Part 4" teases the Triceraton invasion at the end of the episode.
Mikey's pet cat Klunk, who appeared in the original TMNT comics, makes his first ever appearance outside of the comics in this episode.
This episode is based on the Mirage comic "The Christmas Aliens" from Michaelangelo #1.