Ladder

Ladders are objects first seen in original Donkey Kong game. They have reappeared throughout many later games as inanimate objects that the player is able to climb to progress in the level, area or stage. As shown in Super Paper Mario, Bowser is unable to climb up the Ladder, most likely due to his size. If he tried, he would struggle and mutter "Can't climb this!".

Donkey Kong
They are found throughout the stage and serve as a connection between two ramps. Mario has to use them in order to get to the top and to avoid Barrels and Trouble Bugs. Some of the Ladders are broken; Mario cannot climb these. He also cannot climb any Ladders if he is carrying a Hammer. The Ladders in the 50m stage gets disconnected and connected over time.

New Super Mario Bros. games
The only level to feature ladders in New Super Mario Bros. Wii is World 2-4. Here, while strong gusts blow, the ladders are pushed up, turning them unclimbable.

Donkey Kong '94
Ladders reappear in Donkey Kong for the Game Boy in several varieties. The static ladders from the original arcade game make a return in many levels of the game. Mario can only climb a ladder if he stands on solid ground, which is an important element in some levels, where he first has to place a Road or jump on an icicle to have a platform to stand on from which he can climb the ladder. Some ladders in the game are also opening and closing in specific patterns. Mario can only climb those up completely if they are fully open. Another important element in the game's puzzles are ladders than can be placed by Mario himself. If Mario jumps against a Ladder block in the game, the game freezes and the player has to place the ladder in any free point of the level. The ladder will then extend itself upwards and downwards as far as it can. The ladder is timed, and disappears after the time has passed. This timer indicated with a music that starts playing as soon as the ladder is placed and gets faster gradually. The timer can be reset to 0 if Mario places another ladder within the first ladder's time limit, or any other placeable objects such as Roads, Springs and blocks. After disappearing, the ladder can then be placed with the Ladder block again.

Captain Toad: Treasure Tracker
Ladders also appears in Captain Toad: Treasure Tracker which Captain Toad and Toadette can climb. For reason that ladders are added to the game because they cannot jump.

Other Appearances
Ladders have made appearances as well in Super Mario Bros. 2, New Super Mario Bros. Wii, New Super Mario Bros. U ' s The Mighty Cannonship, Super Mario Land ' s Bonus Game, Super Paper Mario, Mario vs. Donkey Kong, Mario & Wario, Mario Party: Island Tour, Mario vs. Donkey Kong 2: March of the Minis, Mario vs. Donkey Kong: Mini-Land Mayhem!, in Rumble Falls, Captain Toad: Treasure Tracker, 75m stages of Super Smash Bros. Brawl and many more games. Also, they can also be added to custom stages.''

Two ladders also appears in the Luigi's Mansion. One of them appears in Professor E. Gadd's laboratory, though it serves no function.