Bag Man...or "Paper Bag Head Spider-Man"...is based on an issue where Spidey went to the Baxter building to get the black costume analyzed. The discovered it was a symbiote living off Peter Parker, and they removed it and locked it up. When Peter had to get home, he borrowed an FF uniform and wore a paper bag over his head (and a "Kick Me!" sign he didn't know the Torch slapped onto his back) and went home.
Of course, the symbiote eventually escaped and eventually became Venom. Peter eventually wore a normal clothes black costume, as well as dozens of other suits.
