The Transdimensional Trapdoor is an item added by the Dimensional Doors mod. It is similar to Warp Doors and Dimensional Doors in that it can transport the player between dimensions. The Transdimensional Trapdoor has its own particular use, however. You can use it to return to the overworld from any Pocket Dimension. Warp Doors will send the player one step closer to the overworld, whereas the Trapdoor will send the player directly to the overworld. However, if the player did not enter a pocket dimension through a rift, it will instead teleport the player directly to Limbo, even if they are just one layer in. USE WITH CAUTION.