History
When an army of Beasts from all over Battleworld was assembled by the sentient bacterial lifeform Sublime so he could seize control of the Phoenix Force, Magneto's X-Men were forced to work with the old X-Men to fight the army off. The Stepford Cuckoos joined with Emma Frost in order to combine their psionic powers to shut down the minds of the Beasts one at a time. However, Sublime took control of Mutopia's Beast and forced him to kill Esme Cuckoo to break the psionic link between Cuckoos and Frost.[1]