Just point-form since my other post never made it.

-Never Played COC nor DG (sounds too dang depressing)

-Unicorn morphs a little section of Lovecraft Country into a Lilac Wood of perpetual Spring, with it's own little colony of feral children (some having grown into feral young adults who are having feral babies), who eventually begin acting more like forest beasts than humans.

This colony acts as the "cult" for the Unicorn, acting to bring runaways and street kids under the protection and tranquility of their world (up to and including kidnapping kids out of shelters of questionable safety). Although it operates on Blue-and-Orange morality, a basic sense of sympathy and protectiveness can be identified when communicating with the Unicorn.

-Investigators investigate, bringing tommy guns, pistols, shotguns and dynamite. Turns out they're being wrong-genre-savvy. They lay siege to the place after witnessing the healing power of the beast after a fight with a few of it's "attendants".

-Miskatonic student eventually brokers a deal with this thing... potential ally with Investigators/Delta Green/Whatever and it lets (or makes) the kids go back to the human world. Gives a "keep your trees green and yourself safe" speech upon leaving negotiations. However, he's made enemies of the more militant, scorched-earth elements of the organization after avoiding a full-on napalm attack. They think he's gone borderline cultist on them.

-also... he's been changed. Functional, but steady at about 3 Sanity points with the conviction that his fellows are entirely too gun-happy and intolerant of the more benign eldrich whazits. The Glamour of this thing never truly wore off, nor did some of its "magic". It doesn't help that if you stare into his eyes, you can't see your reflection, but merely that of that same forest from so long ago.

Now, have I mutilated the genre or what?