World 1-3 (Super Mario Bros. 2)
World 1-3 is the third level of World 1 in Super Mario Bros. 2.
The level features a hidden warp to World 4. Right before the castle, there will be a cluster of plants, one of which is a magic potion. The player must take the magic potion past the castle to a vase. Then player needs to use the magic potion to create a door; once through, they can enter the vase while still in Subspace to warp to World 4.