Gwenpool has always used her comics knowledge to play fast and loose with the established rules, and one series released back in 2019 brilliantly exemplified that idea. Gwenpool Strikes Back (by Leah Williams and David Baldeon) pitted its lead against some of Marvel's heaviest hitters, hoping to shake-up the status quo. During the series, Gwenpool shot Bruce Banner in the head, triggering his transformation into the Immortal Hulk.
In order to stop the enraged monster in Gwenpool Strikes Back #4, the titular antihero took a dip into continuity and broke the rules in a way that shouldn't have worked. Reasoning that the only thing powerful enough to stop the Hulk was Thor's hammer Mjolnir, Gwenpool utilized her metafictional abilities to dive into the history of Marvel Comics to retrieve it. Knowing that she was not worthy to directly wield Mjolnir, however, she first retrieved Thor's severed arm, wore it like a glove, and then used it to wield Mjolnir against Hulk.
How Gwenpool Was Able to Wield Thor's Hammer
There are a few problems with that. Obviously the attempt is made in order to circumvent the worthiness enchantment on Mjolnir, which reads "Whosoever wields this hammer, if he be worthy, shall possess the power of Thor!" To the unworthy, the hammer cannot be lifted no matter how strong they may be, and since Gwenpool knows herself to be unworthy she sought to use the arm of someone who was. The first problem was getting an arm that wasn't attached at the time.
Since she's savvy in her comics lore, Gwenpool dove back to a time shortly after the villain Malekith dismembered the God of Thunder in Thor #2 and took his arm. Evidently Malekith kept the limb for himself like a prized possession -- so prized that he cuddled with it at night like a teddy bear. Gwenpool needed only to slip the arm out of the sleeping Malekith's grasp and it was all hers to use as a disgusting skin sleeve. There's just one major problem the comic didn't address: that arm should not have been worthy.
Malekith cut Thor's arm off around the time he became unworthy to wield Mjolnir's power and Jane Foster began serving as Thor. That means that Gwenpool's entire plan should've fallen apart.
Even setting aside the problem with a wielder only needed the DNA of someone who was worthy in order to make themselves worthy, Gwenpool still made a poor choice. She could have chosen almost any dismembered arm and it would have had the same effect, so either the detail is altogether wrong or hints at something greater.
The "something greater" seems to have two explanations. The simplest would be that Thor himself actually was worthy during the time from which Gwenpool retrieved his arm, and simply unaware of it because he didn't test whether or not he could lift Mjolnir during some brief window of time. The other likely explanation, for a Gwenpool comic at least, would be that Gwenpool herself is worthy and simply doesn't realize it.
Such a revelation would be appropriate for her miniseries, wherein the entire plot revolves around Gwenpool vying for an ongoing solo title in order to keep herself "alive" in continuity. Discovering that she was worthy would have been a great way to wrap the miniseries up and give the character a vote of confidence in herself. The discovery could have given Gwenpool a classic hero's ending in which she discovers that she always had the power within herself - even if she had to experiment with a disembodied arm to figure that out.