World 8-Hand Traps
From the Super Mario Wiki
The Hand Traps are three levels of Dark Land in Super Mario Bros. 3. On the map, there appear to be five traps, though only the ones on the left, center, and right are levels. They can be accessed after clearing World 8- and beyond them is World 8-. When a player moves over them, Mario will either be dragged down by a hand or be allowed to pass. The player also has the option of playing the level on their own. Clearing any of the levels will reward the player with a Super Leaf at the end, and the player will not be able to re-enter the levels.
Despite the levels being castle-themed, the underground music plays instead.
First Hand Trap
The first Hand Trap (on the right) starts off with the player facing against a Fire Brother, the only other one in the game since Desert Land. Afterward are some Brick Block formations with Hammer Brothers on them, and a power-up can be found in one of the blocks on the bottom row. Using the blocks to get over a ledge, the player will then encounter a Boomerang Brother followed by a Sledge Brother before the Warp Pipe to the end of the level.
Second Hand Trap
The second Hand Trap (in the center) has the player jumping over a pool of lava by using the seven small platforms spread across it. Several Podoboos will jump out of the lava between the gaps, and there are many coins above the platforms. After crossing the lava, the player will come across the Warp Pipe to the end of the level.
Third Hand Trap
The third Hand Trap (on the left) is the longest of the three. It has the player run along a long bridge while Cheep-Cheeps jump out of the lava below. The bridge is broken up in several places and there are a couple of Wood Block pillars, both of which the player needs to jump over. Over the sixth platform is a ? Block containing a power-up, and directly afterward is a low pillar the player can either slide under or use the ? Block as a platform to jump over. At the end of the long bridge is the Warp Pipe to the end of the level.