The Bunny Burrow is a location in the adventure Return of the Phantoms. It is used where the player receives the Phantom Key, which allows them to open the Phantom Door. It is the home of George, Clover and presumably Binky (she states that George and Clover are her parents and is directly outside), three bunnies. The Bunny Burrow is guarded by Binky before the player revives all of the plants with the water pails (12 for hard mode, 8 for normal), but the door opens and she allows them to enter after the player waters all of them.
When the player enter the Burrow, they must walk down to the deepest room. Clover waits for them there. She states that she found the Phantom Key and that she thinks that it opens the Phantom Door "over there by the tall grass." The Phantom Key will then appear for the player to pick up and unlock the phantom gate.
The items placed in the Bunny Burrow change once in a while.
The middle room of Bunny Burrow.
The other half of the room where you find the Phantom Key.