Saitama vs. Vaccine Man

Saitama vs Vaccine Man is the battle between the hero Saitama and the Dragon level monster Vaccine Man

Prologue
Vaccine Man attacks Z-City and defeats Smile Man and Lightning Max. Saitama sees the news report and decides to go out to save the day.

Battle
When Vaccine Man attempts to kill a little boy but Saitama save the child. Saitama introduces himself then Vaccine Man while transforming tells Saitama about his origins. As Vaccine Man is about to attack Saitama punches him killing him.

Aftermath
After Saitama defeats him he is seen pounding his fist in anger because of the lack of a challenge he faces. Credit for defeating Vaccine Man went to King who happened to be there at the time.