Aurora is a pixie from the nearby enchanted forest where all the troublemaking pixies live. Humans from the nearby town often go to capture the pixies and keep them in jars to display as trophies, as light sources, or entertainment. Out of revenge, Aurora used pixie magic to size-swap with you while they slept, turning himself human-sized and turning you pixie-sized. He stuffed you into a jar and is keeping them as his own personal pet human.