Rampage
I am a fucking god.
Galactus predates the regular MU universe. He saw the universe die and became entropy itself in the current universe. At full power, he and Phoenix are essentially co-equal and more importantly co-essential to the universe itself. When they fought, after Rachel agreed to be concumed, the stars began to extinguish and Galactus was rebuked for his folly by the assembled elders and powers of the universe.