Unicorn

The urban unicorn is the most dangerous creature in Fairtree, with territories scattered across the city. They are extremely territorial, with an uncanny ability to find those who have offended them no matter where they hide (as long as it's in Fairtree.) Being close to one is said to be a mind-altering experience even if you haven't trespassed against them, and the wise Fairlian avoids getting too close.
While unicorns eat in the normal fashion, they also consume other things of a more abstract nature. There's no evidence that they reproduce as ordinary animals do; the oldest unicorns have been here since before Fairtree was moved to its current location, and nobody has ever killed one. It is not known where they come from, or what benefit they get from living in Fairtree.
As of current date, unicorn watchers reckon that there are six unicorns in the city, with uncomfirmed rumors of a seventh one.

These are the six known unicorns (listed by their common nicknames) and their primary territories:

• "Rune" (The Empty District)
• "Calliope" (Iroval Grove)
• "Glyph" (Colorfaire)
• "Midnight" (Underdown)
• "Dragon" (Watercrown)
• "Ikon" (Saint's March)
  — from A Unicorn Watcher's Guide by PixieN

As pretty as belladonna

And just as annoying! Did you know they eat the color from flower gardens?

We know they are connected to emotions, to colors and art—but it seems to be a tumultuous relationship. They can consume strange thing: not just colors and emotions and magic, but tastes, sounds, dreams. They are the most terrifying art critics one can imagine—and their tastes do not always align with Fairlians.

Unicorns are most commonly sighted in the Ruins or in natural spaces, but they've been recorded all over the city, usually from a safe distance. If one shows up while you're viewing the The Tarnished Mirror, get indoors and stay there until the unicorn moves on!

These are the properties known to be consumed by urban unicorns:

• colors
• emotions (when raised by music)
• meaning (via written words)
• stories (non-destructively)
• memories
• dreams
• light
• sounds
• tastes
• magic force

They also seem to enjoy oral storytelling.