Uni-Pedal-Demon (AKA: UPD)
A middling demon, not a high Demon nor a low demon (imp of the perverse), this demon has one of anything – one eye, one nostril, one leg, one arm, one tusk, one arm, one leg, one finger and one toe (you might think he has two tentacles, but they have bones, so they’re tentacly not technicals 
and one, most definitely, has a palm and a finger – you know which finger it is. 
)
This demon is particularly angry, 
as he feels that he should be the demon in charge of all uni-wheeled vehicles, but as he has only one buttock so he can’t sit on a unicycle seat and therefore can’t master a unicycle (although, if he could he’d obviously be good at one-footed seat-out and hopping!). His singular anger (could he have any other kind?) is the reason there are unexplained UPDs (please note his alias {and you thought it meant unplanned dismount - so gullible}): he waits until after a unicyclist has cleared, with no problems at all, a particularly difficult section and then reaches up and grabs – just for an instant, mind you – the tire (he’s never tyred 
) which, of course, causes the rider to curse the UPD.
Thus is explain-ed those UPDs on perfectly flat, smooth places with nary a stick or stone around.
every time He rides,) He ain’t dead, yet!