Update! Hilarity is now an Alicorn, and the daughter of Molestia. Magic time...
Hilarity in and of herself is one of the ultimate ironies of ponykind. Though perhaps we should build up to that before making such a boisterous claim.
Hillary was her name for the longest time, honestly. Hell, it still is, if you want to get technical about it. Regardless of that point, Hillary was a bright young pony, if not a little bit gullible. She did well in school, and actually discovered her life calling as a psychiatrist early on (as her cutie mark, should it be seen, would prove). However, it was around this time that she herself was having... Episodes. She became obsessed with a television show that was a bit on the bizarre side, starring creatures that ponykind was totally unfamiliar with known as 'humans'. It was just a cartoon, many noted, but Hillary fell in love with it, particularly with its various villains.
As many of you may have guessed, she had a particular affinity towards one of the villainesses, and you have likely all guessed that this show was none other than the 90's iteration of Batman in animated form. So she went about doing what typical radical fans did, going to conventions themed about this peculiar show and often dressing as Harley Quinn... Though, around this time, she began to get little urges and nudges. Soon, she found herself sneakily stealing from other con-goers before she ultimately moved on to full-on heists.
When she was finally caught, she claimed she was no longer 'just little ol' Hillary'. She had become Hilarity, and there was no going back. So she was imprisoned, to be set for a short period of time, just long enough to hopefully teach her a lesson and snap her to her senses.
Then Discord broke free, and in the process disrupted magic in the realm to a point where Hilary was allowed to escape into a bizarre realm where not only humans were real, but they were doing bizarre things that she certainly hadn't seen on TV. In time, she came to learn and experience many of these things, shaping her into the little deviant she is today.
Vore? Yeah, she's aware of it. Sex? Certainly heard of it, if nothing else. A lady never plays her hand too early, especially one such as Hilarity. Though maybe you'll get to see her true colors, in time...
-Encounters of Note-
Sunday March 11, 2012: A chance encounter with Princess
Molestia during one of her many trips to the realm of the Nexus ended rather well, surprisingly. Hilarity let off that she was playful enough for the Princess to take advantage of, and by the end of it she had Molestia shoved up in her plothole! By the end of the ordeal, Molestia offered to take on Hilarity as an heir of sorts in one fashion or another, a successor, though the little pony feels a bit pressed as far as that decision goes, as royal life may mean the sacrifice of her freedom. Then again, it certainly hasn't stopped the Princess.
May 10-20th: Hilarity seems to have had some downtime, but has now emerged as an Alicorn due to being unbirthed and reborn through Princess Molestia. Admittedly, though, her horn's rather sensitive at this stage, and just poking it could even send her into a sensory overload...
((In the works, folks. Generally open character, but talk to me OoC before just making IC approaches in whispers.))