UsefulMutation

v1.0.0·Updated 2026-10-05

New experimental perk for the Silo campaign: Useful Mutation grafts a fully working third hand (-10% max stamina, -10% climb speed). Grip with the mouse wheel.

About this mod Author’s original text

Useful Mutation

A new experimental perk for White Knuckle's Silo campaign.

Useful Mutation

(+) Grafts a third hand between your two hands.

(+) Hanging load is shared across every hand you hang from.

(-) -10% max stamina on ALL hands

(-) -10% climbing speed

It itches. It also grips.

Getting the perk

The perk is added to the experimental terminal (the experimental computer in the Silo break room, the one that

sells experimental perks). It appears in the pool next to the vanilla experimental perks, with its own card art and a

six-fingered-hand icon. You can also grant it from the console with addperk usefulmutation_third_hand.

Using the third hand

The third hand sits at the bottom centre of the screen, between your two normal hands, and works like them: it grabs

handholds, shares the climbing load, drains and regenerates stamina, and can use buttons and levers.

| Input | Action |

| --- | --- |

| Hold middle mouse button (wheel click) | Grip with the third hand, release to let go |

| Scroll up | Grab (stays gripped until you scroll down or the hand lets go) |

| Scroll down | Release |

The third hand has no item slot, so it cannot pick up or hold items.

Configuration

BepInEx/config/com.usefulmutation.whiteknuckle.cfg (created on first launch):

| Setting | Default | Meaning |

| --- | --- | --- |

| Control | Both | Both, WheelClickOnly or WheelScrollOnly |

| ShareStaminaLoad | true | Split hanging stamina drain across all hanging hands (vanilla splits it across two) |

| SpawnWeight | 1 | Relative chance to be offered by the experimental terminal |

| MaxStaminaPenaltyPercent | 10 | Max-stamina penalty on all hands |

| ClimbSpeedPenaltyPercent | 10 | Climbing-speed penalty |

| HandOffsetX/Y/Z, HandScaleMultiplier | 0 / -0.12 / 0 / 1 | Where and how big the third hand is drawn |

| HudIconOffsetX/Y | 0 / 0 | Nudge the third hand's crosshair/stamina icon (pixels) |

Balance values are read when the game starts.

Custom sprites

Until dedicated artwork exists, the third hand reuses the left hand's sprites. To replace any art, drop PNG files into

BepInEx/plugins/-UsefulMutation/Assets/ (create the folder if needed):

| File | Replaces |

| --- | --- |

| perk_icon.png | Perk icon (32x32) |

| perk_card.png | Terminal card art (64x128) |

| hand_normal.png, hand_grab.png, hand_open.png, hand_crouch.png, hand_sprint.png | Third hand poses |

Pixel art should use point filtering-friendly, hard-edged pixels; the game renders everything unfiltered.

Compatibility and notes

  • Requires BepInEx 5 (BepInEx-BepInExPack-5.4.2305).
  • The perk is marked non-competitive, so it will not be offered in competitive game modes.
  • Saves that contain the perk need this mod installed to load. Remove the perk (console clearperks) before uninstalling.
  • Mods that assume the player always has exactly two hands (for example hand-position syncing in multiplayer mods) may

not show or sync the third hand.

  • While you are using a computer terminal the third hand is hidden, because vanilla only positions two hands there.

Source

Source code and build instructions are in the project repository. Build with dotnet build and package with

build.ps1.

Install & use Install: follow the bundled instructions

  1. Unzip the archive from playbuff and read the bundled readme / instructions first.
  2. Most mods rely on the game's mod loader — the usual route is a community mod manager (such as r2modman): pick this game, install, and it handles the loader and dependencies.
  3. For a manual install, put the mod files into the matching Mod / plugins folder inside the game directory.
  4. Launch the game to confirm it loaded; mods with listed dependencies need those installed as well.

Install locations vary a lot between mods — the bundled readme is the most reliable guide.

Dependencies

Install these first, or the mod will not work:

BepInEx-BepInExPack

File & checksum

Filename
UsefulMutation-1.0.0.zip
File size
111.5 KiB