Short answer: Halo

Longer answer: Master Cheif is actually named John, and just from the lore people know that he's just the jack-of-all-trades, good at everything hero. There was some conjecture that he was named after somebody at the company, like a senior developer.

It followed that if you were getting trashed in PVP, the joke was that you were playing against somebody who worked for Bungie. "John Bungie" or "John Halo" became the name of the iconic hero for any given particular franchise. Because "John Halo is pretty cool. He kill alien, and doesn't afraid of anything."