Before the story continues, the author feels that it is important to explain the physiology of the unicorn horn. For the duration of this interlude, he will cede the narrative to a passage from Commodore Guff's seminal work, The Planeswalker's Guide to Ungula, Vol. I: Equestria and Ponies.

The Unicorn Horn

As has been previously noted, Equestria is a notably magical land in an already notably magical plane. You can't swing a cat* inside its borders without hitting three enchanted objects. Oftentimes, one of them is the cat. Still, even in comparison to this high bar, Ungulan unicorns are quite magical in their own right. As with pegasi, unicorns of Ungula are far removed from the more typical specimens sprinkled throughout the Multiverse. As with all subspecies of Equunculus filia, they are as intelligent as humans, with the full range of possible mental faculties that comparison implies. Indeed, in the unicorns' case, there is a slight weighting towards the smarter end of that bell curve, given the unique physiology of their horns.

Unlike that of the larger, less talkative unicorns you are likely more familiar with, an Ungulan unicorn's horn is less like the rack of an elk and more like the horn of a rhinocerous. However, even this comparison falls flat once you look below the surface, both literally and figuratively. The outermost layer of both is composed of keratin, though the unicorn's tends to grow with a gradual curl to it, resulting in the signature spiral fluting.

Beneath the first layer of superstiff hair protein, it's a much different story. While the rhino just has more keratin, the unicorn has the thaumic cortex, a highly specialized nervous organ designed to create and manipulate magical energies. Despite its name, the cortex recapitulates the structure of the entire brain, including the cerebellum minoris, seat of magical "muscle memory", and the cornic lobe, which carries out the behind-the-scenes complexities of spellcasting much as a human child's brain can nigh-instantaneously perform the calculus needed to anticipate the future position of a ball midflight and thus catch it.

Indeed, the thaumic cortex is so complex, it technically qualifies as a second brain in its own right. While it is normally content to manage magical matters, moments of what has been dubbed "extraconscious activity" have been documented. These episodes usually occur during adolescence, as the still-developing cortex, for lack of a better word, experiments. It is possible that the thaumic cortex's constant exposure to self-generated magical radiation gives it some degree of precognition, as these episodes never prove harmful to the young unicorn, and often point him or her in the direction of his or her special talent**.

As of the last time I checked, no connection has been made between extraconscious activity and the slightly higher tendency in unicorns to develop mental disorders when compared to other pony subspecies, particularly dissociative identity disorder.

*Note: Do not swing cats inside Equestria. Not only should you not swing cats on general principle, their owners are far more capable of caving in your skull than the average villager, and explaining away that kind of thing is always awkward for all involved parties.
**See Cutie Marks, p. 262

Telecornesis 1UU
Tribal Enchantment — Unicorn
Other Unicorns you control have "U, T: Tap or untap another target permanent."
Fingers are overrated.