How do I increase/decrease the size of R6 characters through a script?

I found this code, it may kill the player but it almost always works (depending on what I read, I did not try it), it also has a gui, if you do not want the gui, delete it

which it says that it is not from him, it is from a video

function giant(p, size) 
    local pchar = p.Character
    if pchar then
        local function scale(chr,scl)

            for _,v in pairs(pchar:GetChildren()) do
                if v:IsA("Hat") then
                    v:Clone()
                    v.Parent = game.Lighting
                end
            end

            local Head = chr['Head']
            local Torso = chr['Torso']
            local LA = chr['Left Arm']
            local RA = chr['Right Arm']
            local LL = chr['Left Leg']
            local RL = chr['Right Leg']
            local HRP = chr['HumanoidRootPart']

            wait(0.1)

            Head.formFactor = 3
            Torso.formFactor = 3
            LA.formFactor = 3
            RA.formFactor = 3
            LL.formFactor = 3
            RL.formFactor = 3
            HRP.formFactor = 3

            Head.Size = Vector3.new(scl * 2, scl, scl)
            Torso.Size = Vector3.new(scl * 2, scl * 2, scl)
            LA.Size = Vector3.new(scl, scl * 2, scl)
            RA.Size = Vector3.new(scl, scl * 2, scl)
            LL.Size = Vector3.new(scl, scl * 2, scl)
            RL.Size = Vector3.new(scl, scl * 2, scl)
            HRP.Size = Vector3.new(scl * 2, scl * 2, scl)

            local Motor1 = Instance.new('Motor6D', Torso)
            Motor1.Part0 = Torso
            Motor1.Part1 = Head
            Motor1.C0 = CFrame.new(0, 1 * scl, 0) * CFrame.Angles(-1.6, 0, 3.1)
            Motor1.C1 = CFrame.new(0, -0.5 * scl, 0) * CFrame.Angles(-1.6, 0, 3.1)
            Motor1.Name = "Neck"

            local Motor2 = Instance.new('Motor6D', Torso)
            Motor2.Part0 = Torso
            Motor2.Part1 = LA
            Motor2.C0 = CFrame.new(-1 * scl, 0.5 * scl, 0) * CFrame.Angles(0, -1.6, 0)
            Motor2.C1 = CFrame.new(0.5 * scl, 0.5 * scl, 0) * CFrame.Angles(0, -1.6, 0)
            Motor2.Name = "Left Shoulder"

            local Motor3 = Instance.new('Motor6D', Torso)
            Motor3.Part0 = Torso
            Motor3.Part1 = RA
            Motor3.C0 = CFrame.new(1 * scl, 0.5 * scl, 0) * CFrame.Angles(0, 1.6, 0)
            Motor3.C1 = CFrame.new(-0.5 * scl, 0.5 * scl, 0) * CFrame.Angles(0, 1.6, 0)
            Motor3.Name = "Right Shoulder"

            local Motor4 = Instance.new('Motor6D', Torso)
            Motor4.Part0 = Torso
            Motor4.Part1 = LL
            Motor4.C0 = CFrame.new(-1 * scl, -1 * scl, 0) * CFrame.Angles(0, -1.6, 0)
            Motor4.C1 = CFrame.new(-0.5 * scl, 1 * scl, 0) * CFrame.Angles(0, -1.6, 0)
            Motor4.Name = "Left Hip"

            local Motor5 = Instance.new('Motor6D', Torso)
            Motor5.Part0 = Torso
            Motor5.Part1 = RL
            Motor5.C0 = CFrame.new(1 * scl, -1 * scl, 0) * CFrame.Angles(0, 1.6, 0)
            Motor5.C1 = CFrame.new(0.5 * scl, 1 * scl, 0) * CFrame.Angles(0, 1.6, 0)
            Motor5.Name = "Right Hip"

            local Motor6 = Instance.new('Motor6D', HRP)
            Motor6.Part0 = HRP
            Motor6.Part1 = Torso
            Motor6.C0 = CFrame.new(0, 0, 0) * CFrame.Angles(-1.6, 0, -3.1)
            Motor6.C1 = CFrame.new(0, 0, 0) * CFrame.Angles(-1.6, 0, -3.1)

        end

        scale(pchar, size)
        pchar.Humanoid.WalkSpeed = 15 * size

        for _,v in pairs(game.Lighting:GetChildren()) do
            if v:IsA("Hat") then
                v.Parent = pchar
            end
        end
    end
end

local plr = game.Players.LocalPlayer
giant(plr,1)


local csize = 1

local sgui = Instance.new("ScreenGui", game.Players.LocalPlayer.PlayerGui)
local base = Instance.new("Frame", sgui)
base.BackgroundTransparency = 1
base.Size = UDim2.new(0, 110, 0, 200)
base.Position = UDim2.new(1, -120, 1, -180)
local indicator = Instance.new("TextLabel", base)
indicator.Size = UDim2.new(1, 0, 0, 25)
indicator.TextColor3 = Color3.new(1, 1, 1)
indicator.BackgroundTransparency = 0
indicator.FontSize = Enum.FontSize.Size18
indicator.Font = Enum.Font.SourceSans
indicator.Text = "Current Size: 3"
local PlusOne = Instance.new("TextButton", base)
PlusOne.BackgroundColor3 = Color3.new(214/255, 214/255, 214/255)
PlusOne.Position = UDim2.new(0, 0, 0, 40)
PlusOne.Size = UDim2.new(1, 0, 0.5, -50)
PlusOne.BorderSizePixel = 2
PlusOne.Font = Enum.Font.SourceSansBold
PlusOne.FontSize = Enum.FontSize.Size24
PlusOne.Text = "+.1 Size"
local MinusOne = Instance.new("TextButton", base)
MinusOne.BackgroundColor3 = Color3.new(214/255, 214/255, 214/255)
MinusOne.Position = UDim2.new(0, 0, 0.5, 10)
MinusOne.Size = UDim2.new(1, 0, 0.5, -50)
MinusOne.Text = "-.1 Size"
MinusOne.BorderSizePixel = 2
MinusOne.Font = Enum.Font.SourceSansBold
MinusOne.FontSize = Enum.FontSize.Size24

PlusOne.MouseButton1Down:connect(function()
    csize = csize + .1
    giant(plr, csize)
    indicator.Text = "Current Size: "..tostring(csize)
end)

MinusOne.MouseButton1Down:connect(function()
    csize = csize - .1
    giant(plr, csize)
    indicator.Text = "Current Size: "..tostring(csize)
end)