Rumbelle in Belle's dream world.

Dream Worlds are realms featured on ABC's Once Upon a Time. They are the manifestations of one's dreams, accessible only to the person sleeping - and dreaming it into existence - or to people who can insert themselves into others' dreams via the Sands of Morpheus or by other means.

Known Dream Worlds

Regina's Dream World

Regina has a dream that the heroes abduct her, tie her to her apple tree and execute her.
She has another dream where she is reunited with Robin Hood, but they are attacked by the Evil Queen.

Belle's Dream World

Belle has a dream that Rumplestiltskin attacks Grumpy. She also has another dream which Rumplestiltskin and their unborn son insert themselves into in order to communicate with Belle, who is under a Sleeping Curse. Afterwards, her son Gideon still managed to access her dreams and communicate with her.

Rumplestiltskin's Dream World

Rumplestiltskin has a dream that he kills his grandson Henry.

David's Dream World

David has a dream that he is briefly reunited with Emma, until the latter is sucked into a portal.

Snow's Dream World

Snow has a dream that she is threatened by the Queens of Darkness.

Emma's Dream World

Emma has a dream or a vision that Snow is attacked by a wolf.