Swansong, an exiled changeling, is living in Equestria; surviving by any means she can. There’s a reason it’s considered Equestria’s second oldest profession. Swansong ekes out a living as best she can, until she finds herself in an impossible situation; she has laid an egg, a privilege normally restricted to the Queen’s brood.

As the the little hatchling grows, Swansong knows something is wrong. The child eats regular pony food, and she feels the love emanating from it. Her fellow changelings would either steal the child as a resource, to be fed on until she died; or they would kill her as an abomination.

She knows this, because being around the child makes her hungry herself.