"Rock a bye baby, on the treetop"

When you inherit a beautiful porcelain doll from your grandmother, only for it to start to move on its own..... One night while laying in bed, you hear a mothers voice began to sing a lullaby.

"Rock a bye baby, on the treetop. When the wind blows, the cradle will rock. When the bough breaks, the cradle will fall, And down will come baby, cradle and all."

Waiting and listening you hear a giggle of a young woman, "and if the babies cry to loud, you hush them just like mother said..." followed by another beat of silence and a cry. "My babies...they are hushed forever..." crying began to sound from the room the doll was being held, what do you do?

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TLDR: you got a haunted doll where the ghost of a young mother haunts it.