Fence

A Fence is an object found in Super Mario World and in New Super Mario Bros.

These fences only occasionally appear in Castles as Mario or Luigi can use it to go around traps like the Lava. The brothers can jump and climb on and jump off it as well. Koopa Troopas also appear to climb on the fence and move around as they can go around both sides of the fence. The brothers may also be able to punch on them to knock the Koopas that are on the other side and to flip to the other side by punching a square panel to flip Mario or Luigi.

In Super Mario Sunshine, several fences were able to be used in the same way. Several of these created boxes, which enclosed enemies and coins, though some were flat, like the originals. Theses types of Obstacles appeared in Ricco Harbor, Pinna Park and Pianta Village and can be used to knock off enemies from the other side.

They also reappear in New Super Mario Bros. Wii as obstacles in Towers and Castles.

Appearances in Other Media
A small Fence made a brief appearance as an obstacle in Neon Castle in the Super Mario World animated series episode "Mama Luigi". Mario, Luigi and Yoshi are able to easily pass this gate by simply using its revolving door.