Flash speed

local player = game.Players.LocalPlayer

local gui = Instance.new("ScreenGui")
gui.ResetOnSpawn = false
gui.Parent = player:WaitForChild("PlayerGui")

local button = Instance.new("TextButton")
button.Size = UDim2.new(0,160,0,50)
button.Position = UDim2.new(0.5,-80,1,-70)
button.Text = "SPRINT"
button.TextScaled = true
button.BackgroundColor3 = Color3.fromRGB(255, 221, 0)
button.Parent = gui

local sprinting = false
local normalSpeed = 16
local sprintSpeed = 40

button.MouseButton1Click:Connect(function()
	local character = player.Character or player.CharacterAdded:Wait()
	local humanoid = character:WaitForChild("Humanoid")
	local root = character:WaitForChild("HumanoidRootPart")

	sprinting = not sprinting

	if sprinting then
		humanoid.WalkSpeed = sprintSpeed

		local cloud = Instance.new("Part")
		cloud.Shape = Enum.PartType.Ball
		cloud.Size = Vector3.new(8,4,8)
		cloud.Color = Color3.fromRGB(80,80,80)
		cloud.Material = Enum.Material.Slate
		cloud.Anchored = true
		cloud.CanCollide = false
		cloud.Position = root.Position + Vector3.new(0,15,0)
		cloud.Parent = workspace

		local bolt = Instance.new("Part")
		bolt.Anchored = true
		bolt.CanCollide = false
		bolt.Material = Enum.Material.Neon
		bolt.Color = Color3.new(1,1,0)
		bolt.Size = Vector3.new(0.6,15,0.6)
		bolt.Position = root.Position + Vector3.new(0,7.5,0)
		bolt.Parent = workspace

		local sound = Instance.new("Sound")
		sound.SoundId = "rbxassetid://130818250"
		sound.Volume = 2
		sound.Parent = root
		sound:Play()

		game:GetService("Debris"):AddItem(sound,3)
		game:GetService("Debris"):AddItem(cloud,1)
		game:GetService("Debris"):AddItem(bolt,0.2)

		local fire = Instance.new("Fire")
		fire.Name = "SprintFire"
		fire.Color = Color3.fromRGB(255,255,0)
		fire.SecondaryColor = Color3.fromRGB(255,170,0)
		fire.Size = 12
		fire.Heat = 15
		fire.Parent = root
	else
		humanoid.WalkSpeed = normalSpeed

		local fire = root:FindFirstChild("SprintFire")
		if fire then
			fire:Destroy()
		end
	end
end)

local RunService = game:GetService("RunService")

RunService.RenderStepped:Connect(function()
	if sprinting then
		local character = player.Character
		if character then
			local root = character:FindFirstChild("HumanoidRootPart")
			local humanoid = character:FindFirstChild("Humanoid")
			if root and humanoid and humanoid.MoveDirection.Magnitude > 0 then
				if not root:FindFirstChild("RunLightning") then
					local s = Instance.new("Sound")
					s.Name = "RunLightning"
					s.SoundId = "rbxassetid://130818250"
					s.Volume = 0.5
					s.Looped = false
					s.Parent = root
					s:Play()
					game:GetService("Debris"):AddItem(s,1)
				end
			end
		end
	end
end)