I was sad that Megamind's planet and people were dead, so I wanted an alternate storyline where the black hole that swallowed them instead spit them out into some kind of timeless void, from which they managed to escape much later. Essentially, they became a wandering people on a "mothership" without a planet, traveling for many long years.
Megamind's parents are also there, having long lost hope of finding their son or even believing he survived. But over time, they pick up a signal from Megamind's dummy, and that's how they arrive on Earth.
Aside from a very dramatic and tearful reunion, there's also the storyline of Megamind's people searching for a new home—and of course, one option is to stay and live on Earth. But for that to happen, both they and the humans need to adapt.
This is where I came up with two original characters and a separate plot thread:
Sola is an emissary sent on behalf of Megamind's people to represent them to humanity. She is ambitious, flexible, and open to making contact. The way she presents her people will directly determine whether they finally gain a home on Earth.
Ariston is her friend and partner in this peaceful mission... essentially, he's the embodiment of Spock, because I couldn't resist. Strict, all logic, and no unnecessary emotions (except for the fact that he's hopelessly in love with Sola—though he doesn’t understand it himself, nor can he show it, which leads to plenty of misunderstandings and arguments between them). He also cares deeply about the safety of his people and dislikes humans, viewing them as savages. However, he has to keep quiet about it, because yes, they need a home—and there aren’t that many habitable planets left.