Brain-Child is a fictional character in the Marvel Universe.
When the Avengers were attempting to return home from another dimension, they were accidentally shunted to the Squadron Supreme's Earth. Discovering that the world was about to be destroyed by an overactive sun, the Scarlet Witch was able to send the Avengers back in time by a week.
At that point in time, Brain-Child had designed a rocket to cause the sun to go super-nova, although he had duped the world into believing the rocket was a simple probe designed to circle the sun. The Avengers, having knowledge of the immediate future, convinced Nighthawk of the Squadron Supreme of what they had seen, so the two teams travelled to Brain-Child's tower to investigate. Brain-Child attacked the heroes with his numerous technological devices, but Hawkeye, in his Goliath form, used Hyperion as a "arrow" in a makeshift giant "bow" to knock Brain-Child off his throne. Brain-Child, exhausted from the strain on his mind, collapsed to the ground crying for his mommy. Doctor Spectrum removed Brain-Child's advanced intellect and memories and returned him to a normal form, and the Squadron Supreme vowed to give him a normal life this time around.