So, I was thinking about this earlier.
There's a pokemon called Nidoran, which looks like a weird rabbit with a horn. Most pokemon designs wear their influences on their sleeve (like the pokemon 'Seel', which is a seal), but it wasn't obvious to me where it came from.
The initial thought I had was that it was based on the jackalope or wolpertinger, but those both have two horns, and as far as I know, are not well-known in Japan.
However, there is an Arabic myth about a one-horned rabbit called an Al-Mi'raj, and the Al-Mi'raj made its way into first-edition Dungeons & Dragons. Lots of Japanese RPGs in the '80s borrowed ideas from D&D, or borrowed from other media that borrowed from it, etc. One of the most popular of these was Dragon Quest.
Dragon Quest was an immediate inspiration for pokemon. In some of those games, you can recruit the monsters you defeat to join your party. It's very likely that pretty much everybody working on pokemon was at least aware of it. Starting with Dragon Quest III, the Al-Mi'raj has appeared regularly in the series, with a distinctive purple color!
So, although I don't have any concrete evidence, it seems very plausible that Nidoran was inspired by this mythological creature, by way of another popular Japanese RPG series. Also, both cute.