I'm not sure this shouldn't go in the Comedy section, but anyway...
In Dungeons and Dragons, one can use the Escape Artist skill to escape from ropes or a grapple, or to squeeze through tight places.
Now, the Epic section of the rules states that skills can do some inhuman things at high levels. If you're rearranging the world with a thought, using a Balance check to keep your balance when standing on clouds isn't such a big deal any more. No, really.
So what does it say for Epic Escape Artist, you ask? Well...
[quote the raven]
Extremely Tight Space: This is the DC for getting through a space when one’s head shouldn’t even be able to fit; this can be as small as 2 inches square for Medium-size creatures. Halve this limit for each size category less than Medium-size; double it for each size category greater than Medium-size. If the space is long, such as in a chimney, multiple checks may be called for.
Now, that's a fairly high difficulty - to reliably roll an 80, you'll need a +70 on your skill. But you can totally do that before 20th level.
So, the clever chaps at 4chan pointed this out: You can actually use that skill to crawl into another person's anus, and conceal yourself there, with no harm done to you or them. Indeed, the entire party, if they all have a +70 to the skill, could conceal themselves into one single bodily orifice. Now, do they hide the party inside a hireling to surprise enemies, or do they cast Hold Monster and hide within a monster?
This is both horrifying and hilarious at the same time. And I just know that those playing Sigil Prep are suddenly terrified, thinking "Will she actually do it?"