Wishing Doll

Description
This small doll resembles the center of a set of Matryoshka Nesting Dolls. If the holder makes a wish, the doll will appear to summon another, larger doll, containing the previous. Each wish makes another doll around the other.

The doll does not actually grant wishes; instead, it traps the user inside the doll, creating an illusionary world where their wish is true.

To the perspective of the person making the wish, the doll manifests an outer layer, and their wish comes true. To the perspective of an onlooker, the person making the wish gets trapped inside the doll before it manifests the layer. In order to escape from the doll, it must be opened both on the inside and the outside; doing so destroys the illusionary world and ejects the person from the world.

The trickiness comes from the fact that the Wishing Doll remains functional inside itself; you can make a wish and be trapped a whole extra layer down! If you're not careful, there may not be anyone on a certain layer to let you out on your way back up!