From Wiktionary, the free dictionary
Derived from pics or it didn't happen, replacing pics with something else that is demanded as proof like links or video.
or it didn't happen
- (Internet, humorous) Unless one can provide the proof that one is requesting, that person has no credibility in the matter.
2014, Jeff Carlson, iPad and iPhone Video: Film, Edit, and Share the Apple Way, Peachpit Press, →ISBN, page 145:To paraphrase a popular Internet meme, share your movie or it didn't happen.