Torch

A Torch is an item you can obtain in certain towers, and if you activate it, begins to glow, but once after a set amount of time, it will be gone from your inventory, since torches do expire after they burn out. This makes an interesting challenge, and there are uses for torches as well.

Uses
A torch can illuminate an area which blends in with the wall, and this can be useful, although players can collide with it anyway, it's one of a few items that players can obtain that you can use for your own good.