Canon: Dinky isn't Derpy's daughter... SHE'S A CHANGELING, AAAAAH. D: · 6:51pm Feb 20th, 2013
No, seriously. She is, take a look.
She's the only kid around with an adult model for her eyes, her cutie mark keeps changing despite not having cutie-pox.
She's a crowd filler that pops up randomly all over the place, with a different cutie mark (Or even no cutie-mark) each time.
Her 'sister' from the Sisterhooves Social... Amethyst Star... Well.