The Japanese shortened name
Wanpanman is a play on the long-running children's character
Anpanman, wanpan being a contraction of wanpanchi ("one punch"). One became interested in creating a comic superhero who was already the strongest in the world
One Punch Man draws inspiration from a children’s anime called
Anpanman.
Anpanman never took off in the West, but it's one of the highest-grossing media franchises of all time, generating over $50 billion in total retail sales revenue.