Uncanny X-Men, Vol. 1 #135 (1980)

Dark Phoenix Saga, Dark Phoenix!
The X-Men are easily defeated by Dark Phoenix, who then leaves Earth looking for something else. Beast arrives in an Avengers quinjet to help the team regroup, but they have no means of tracking Dark Phoenix. Jean, hungry, consumes a G-type star she passes, triggering a nova that slaughters five billion people living in the solar system who were allied with the Shi'Ar. The Shi'Ar decide that Dark Phoenix must be stopped at all costs.
Release Date: 1980