The fog.
He hated fog.
As he crawled to engulf himself in the coolness of a snowpile, the buzzing Summer Fey surrounded him, laughing at the pain they caused him. They all surrounded him, and he whipped them around with Wind. It did nothing but tick them off, and the poor winter spirit was forced to flee again. For what purpose they tormented him for this time, he didn't know.
Weak, tired, and burned by the little creatures, Jack Frost curled up, the pain and exhaustion (for they had pursued and tormented him two days now, giving him no peace) too much for him, and he gazed into the fog, thinking his time was short. The Fey covered him from foot to head, buzzing and burning, swarming like ants on a dead mouse.
Something moved in the milky whiteness...And the Fey were suddenly picked up off of him and flung away, flurries dancing across burned flesh, cooling it with pleasant gentle breaths. Puzzled, he stared at the fog.
There was a glowing light, like a lit sabre, piercing the fog, chasing the heat and pain away. His tired eyes opened wide, as a figure appeared, a figure of power and might, and whiter than the freshest snow. Four powerful hooves stomped some Fey into the ground like fragile bugs being tramped on by an elephant. Glowing blue eyes stared down at the now-awestruck and slightly terrified Winter Spirit. A voice, deep,wise, and gentle, pierced the wooshing wind, though the muzzle did not move.
Sleep now, old friend.
The glowing horn touched him lightly, coating him in healing ice, and sending him into peaceful slumber. The 18-hand equine then lay down, as he had often done at the Pole, and curled up around the sleeping form of his old master, his once surrogate father, and now his colt, and sent into the boy's slumber, memories of a scrawny fawn, playing with the winter sprite once upon a lifetime.