The .avi extension brings back memories of the "Wild West" era of the internet, where users downloaded videos from P2P networks. These files were notorious for being:
: The dual extension is a classic hallmark of trojans.
In internet subcultures, particularly those surrounding obscure animations, gaming modifications, or fan-translated media, filenames are often literal descriptions of a specific scene or inside joke. It is highly possible that this file belongs to a segmented archive of a niche video clip, where a character or "rider" is depicted in a humorous, pants-less scenario. The SEO and P2P Baiting Theory
: How specific, nonsensical naming conventions like this one evolved in the era of P2P (Peer-to-Peer) sharing to bypass filters or simply as a result of chaotic user titling.