getgenv().speed = 100

local Humanoid = cloneref(game:GetService("Players").LocalPlayer.Character or game.Players.LocalPlayer.CharacterAdded:Wait()):WaitForChild("Humanoid")

local meta = getrawmetatable(Humanoid)
local oldIndex, oldNewIndex = meta.__index, meta.__newindex
setreadonly(meta, false)

meta.__index = function(tbl, key)
    return key == "WalkSpeed" and 16 or oldIndex(tbl, key)
end

meta.__newindex = function(tbl, key, value)
    oldNewIndex(tbl, key, key == "WalkSpeed" and getgenv().speed or value)
end

setreadonly(meta, true)
Humanoid.WalkSpeed = getgenv().speed