Despite being a fantasy staple, I think I haven't seen this creature come up more often because:
- They aren't really a "monstrous" monster, aka "Something PCs are likely to fight."
- Very few of my players choose to play young maidens.
Back at Garycon last month, Jeff Rients ran an adventure with an insane unicorn prowling the caves. After that was over, I looked at the thing's stats, comparing it to a war horse (the scariest normal equine).
I just couldn't bring myself to use one of the
seventeen MILLION "sparkly" images Google turned up.
It's faster than a war horse, has a better AC, more HD, and does more damage per attack (1d8 vs. 1d4). NTM it gets a third attack (horn). Unicorns also get that freaky teleport ability, so it'd be hard to finish one off without it escaping, especially with their skittish morale.
A wandering encounter with these creatures has a herd of 1d6 galloping about, which could really spell bad news for someone who decided to mess with them. The 1st edition version is even scarier, with human-level intelligence and a horn that does a d12 damage (doubled when charging!).
All this makes me wonder about a good way to include a unicorn encounter that is not geared toward 8 year-old girls. Perhaps a woodland guardian? Or maybe a reincarnated NPC? Or maybe someone hung the MacGuffin around the unicorn's neck (a la "Amber") and it flits about resisting attempts to capture it? Anyway, it bears further thought.