Comic book character, created by Chris Bachalo and Christopher Hastings for Marvel Comics. She is a fourth-wall-breaking, reality-warping combination of Deadpool and Gwen Stacy who wouldn't even exist without comic geeks' obsessions and comics publishers' addictions to flash-in-the-pan variant covers.
To understand Gwenpool and her creation, you have to be familiar with a couple different characters -- and with a common scheme comics publishers use to sell extra comics.
As for the characters, there is, first, Deadpool, Wade Wilson, the Merc with a Mouth, a wisecracking mutant assassin whose improbable popularity eventually pushed him into movie superstardom. And second, there's Spider-Gwen, an alternate-universe version of Gwen Stacy who managed to acquire spider-powers instead of Peter Parker and whose own improbable popularity had comics fans demanding as much Spider-Gwen content as Marvel could shovel at them.