First appearance of The Colony, the animated series version of the Brood. In the comics, the Brood are a parasitic, insectoid species with organic tentacles that lay eggs inside their victims to transform them into Brood. For the series, they were changed to reptilians with metallic tentacles who infect their victims with some type of spore. The change was made to make them more distinctive and animator-friendly. The comic version of the Brood were previously seen as generic alien soldiers in Mojovision (1994) and Professor Xavier used the illusion of a Brood Queen to frighten the soldiers attacking Iceman (Bobby Drake) in Cold Comfort (1995).
Although the episode aired during Season 4, it was intended to air during Season 3, right after Orphan's End (1995).
This is the first full appearance of Cody Robbins. In most adaptations of the X-Men, Cody is the boy Rogue kissed when she first developed her powers sending him into a decades-long coma. Cody was seen previously during flashbacks involving Rogue's backstory in The Cure (1993) and A Rogue's Tale (1994).
The Colony arrive on Earth in an Acanti, a space-faring creature resembling a giant whale.