My Little Pony fans invade San Diego
Donning rainbow wigs, pony ears and sparkling tails, hundreds of “bronies” attended the first-ever Pacific PonyCon. The three-day convention, centered on "My Little Pony" characters, featured group games, contests, concerts and panels. Ref. Source 2i
Image from Wikimedia public domain...
Ponycon - My Little Pony (Hover)
What might I ask is extreme about it? How is it any different from the comic and anime conventions where fans dress up as their favorite characters from whatever series they may be part of? It may seem odd, though careful on saying it is extreme.
You may be surprised on how many, though most are admittingly probably not on this forum.