A short, wooden ladder.
Allows Isaac to walk across pits one square wide by automatically placing a ladder between the two walkable areas (or between walkable area and room wall).
It also confuses the pathfinding of all non-flying enemies. For example, Globins and Gapers will lose you and stop if you are standing over a pit. This is very useful against all non-shooting, non-flying monsters.
Unfortunately, you can also get briefly stuck on the ladder if you're not careful (for example, if there's gaps along the edge of the room and you place the ladder on one of the gaps), thus leaving you vulnerable to flying or shooting enemies like Maws.
This item is absolutely worthless if you have an item that allows flight, such as Lord of the Pit.
- It is possible to get stuck if you use the ladder to walk onto a tile surrounded by pits with a Stone Grimace or Vomit Grimace. One can also get stuck by quickly moving onto a tile with a Stone Grimace or Vomit Grimace surrounded by pits, as the player will be pushed and trapped between two of them.
- The Ladder is likely a reference to the game The Legend of Zelda, being that in the game the main character uses a ladder in the same fashion to cross gaps, as shown above.de:The Ladder