Alien Alliance Invasion

The 2012 attack by attack on Earth by Annihilus and General Zod of Krypton drew the attention of other alien races.

In 2012, an alien coalition known as "the Alliance" was formed by the Dominators. The various species of the Alliance launched attacks all across the Earth, securing significant ground. Several of Earth's most powerful superhumans formed the Justice League to oppose them. The Fantastic Four provided experimental technology that allowed the members of the JL and the X-Men to be dispatched all across the globe and repel the invasion.

As a last-ditch effort, Kree science mercenaries allied with the invasion force detonate modified Terrigen Mists in the atmosphere. Concentrations are not heavy enough to cause widespread loss of life, but over the following months there is a dramatic increase in recorded metagenetic incidents across the globe.