Dream Ladder is one of the gadgets owned by Doraemon.
Function[]
The user can use this gadget to go to anyone else's dream as they want.
As revealed in The Doraemons Special manga the user, after entering the dream world, can't escape back to the real world after The Nightmare Eater Baku appeared. The same user can't even go to another person's dream unless Baku escaped to the real world and was captured.