A rather strange, not to mention rare variant of the more 'normal' quadrupedal Equestrian changeling, these smaller 'lings resemble a Mew in general body shape, even possessing some of their trademark psychic power, albeit at the tradeoff of their changeling magic being significantly weaker than the norm. The origin of this strange strain is unknown, but they are rumored to have roots in an ancient changeling queen of otherworldly origins and a similar form, often referred to as the 'thousand-formed queen' for their absolute mastery of the strange, psychic-fuelled transformation-capabilities they possessed.
One being born is a rare occurrence and often seen as a sign of good fortune for the world, there is no known way to predict when these may be born, records showing no discernible patterns in caste, breed or even species of the parents beyond one or both being a changeling.

Curiously, a small number of these 'Mew-Lings' have even been reported to have gained enough power to be able to travel the multiverse in search of this lost legendary queen, and subsequently vanished to seek her out.

This is an idea I've had tossing about in my head for a while, a Mew/Changeling(MLP) hybridization of sorts. Maybe I'll get a pic or two more of this in the future but for now it's nice to have a sort of example to look at~

Picture made by the great  immelmann~!