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 you know, you know.

A config file is available to enable/disable the Gear of Madness item and the low temporal stability sound behavior individually.

The config file can be found at 'VintageStoryData/ModConfig/gearofmadnessconfig.json' and will be generated upon first loading of a world with this mod enabled.