In-game item description:

"The rumbling of gears will give birth to insanity even in a sound mind. Can be shattered to induce temporal instability."

This mod adds the titular Gear of Madness, an item dropped from drifters that can be crushed (read: hold right-click) to reduce the player's temporal stability. It also adds an additional gear rumbling sound when at low temporal stability, the volume scaling with how low stability is.

If the Better Drifters mod is also installed, the gears will instead only drop on drifters ranked corrupt or above, and will replace their twine drops.