The PG-13 label comes from the American film rating system, where it signals that some material may be unsuitable for children under thirteen and that parents should be aware. Because the label is instantly recognisable from trailers and posters, short clips that reference it have become a handy shorthand online. Creators use the reference to frame a joke, soften a slightly edgy moment, or pretend a homemade video has passed through a studio ratings board. That shared familiarity is why the gag still lands, even without any particular film attached to it.