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/<author>-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.