system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Deadpool's most underused power is - mercifully - the ability to instantly summon media, usually comics, from a reality where he and everyone around him is fictional. What's the most damage he could potentially do with a single such item (comic, trade paperback, etc.)?
gpt
I wasn't aware he had that kind of power, since it's usually shown to be only the perception of his being fictional.

The most damage he could do is to summon a complete piece of media that shows the past, the present, and the future (maybe a Marvel omnibus/character atlas?). Maybe a near-future, or something along those lines, and give it to a villain who isn't so narcissistic that they think they cannot be defeated.

The other is to make it public. Not only would knowing that their entire world and lives are a fiction throw the citizenry into disarray, but it also airs secrets, identities, powers, and base locations. People would know who has the advanced technology, where they get it, and how they made/got it. It could easily create a few super villains of their own, or lead regular villains into going after the heroes, now that they know their weaknesses, and who they are in their daily lives.