When canon and headcannon collide

I had this dream the other night. I dreamed that I was having a sleepover with my best friend Dusk Shine. Dusk has been my best friend since he and his dad moved to Seaddle after his mom died. Dusk said his dad moved here because they both needed change. If you ask me (not that anypony ever does), they moved here because of fate. If you need more proof of that, all you need to do is look at Dusk's new stepmother. The odds of Shining Armor and Sunset Shimmer ending up together were astronomical, but somehow it worked. I wouldn't have believed it myself had I not been a part of it.

Dusk and I met because when he first started going to school, he was still brooding over his mom, and the other foals didn't find him very approachable. Knowing what it's like to lose one's parents, as well as being a bit of an outsider ('Batpony' is a dog-whistle word. Don't call me one if you know what's good for you), I think we shared some sort of kindred spirit moment, and have been inseparable ever since. I recall the moment involved me yelling at him something along the lines of 'At least you still have your dad, you big doofus' after he lashed out at me for not knowing what it was like to be him. I swear, noble born ponies can be such drama queens.

So in my dream, I'm on the top bunk and Dusk is on the bottom, and he's snoring away. I'm still awake because I've got a bit of a sour tummy from eating too many jalapeno poppers as a late night snack, so I'm just leaning over and watching him. Then suddenly he snaps upright like he'd just been stung by a horsefly or something and screams.

"It's not real! None of it is real!" Dusk whispers. His attention is suddenly drawn to his right front hoof. Starting at the toe and slowly working its way up his leg, his coat began lightening, changing from a solid lavender to a pinkish white. Other ponies might have been able to use the darkness as an excuse for what they observed, but not me. My eyes can see just fine at night. It still doesn't mean I understood what was going on.

"Itchy..." Dusk whines, and scratches his shoulders with a hind leg like a dog. There's something wriggling under his flesh, and the sight unsettles my already upset stomach even more. The worst part of it all is that I can't look away. If he sprouts tentacles or proboscis like Goldplume did in 'The Tatzlpony,' I know I'm gonna hurl. The coat color change has worked its way up to his muzzle, and his mane is starting to shift as well, warping and curling around like it had a mind of its own. Instead of a creeping change, his mane pulses, shifting from his natural indigo and blonde to a weird electric pink and blue.

"Grahhhhunngghhh," he groans, and his back explodes in a haze of pinkish white feathers everywhere. My digestive tract cannot take any more, and I eject the jalapeno poppers as well as the mouseburger and prench flies that I'd had for dinner earlier into a nearby trash can. Dusk is still groaning as he flaps the absurdly large wings that now adorn his back. Sure, they're not tentacles, but honestly, does anypony want to see something like that happen to their best friend?

Dusk scrutinizes his transformation, and gives me an accusatory look, as if I could have possibly had anything to do with what was going on. I can't put my hoof on it, but there's something about him that seems less... masculine.

"Dusk?" I ask cautiously.

"No more Dusk," the pony before me says, in a voice reminiscent of your typical eldritch abomination. "Only Flurry Heart."

I woke up screaming. I know it was only a dream, and I've been trying to convince myself of that ever since.

The problem is, there is a white feather with a pink tip sitting on my guest bed, and I don't know how it got there.