[REMOTE EVENT] Mouse Is a nil Value?

Hi, I'm having trouble figuring this out. Basically it's saying 'Mouse is a nil value' when it's being classified and sent through a Remote Event. Here are some details.

In local script in StarterPack:

local Player = game.Players.LocalPlayer
local Enabled = false
repeat wait() until Player and Player.Character
local Mouse = Player:GetMouse()

Mouse.KeyDown:Connect(function(key)
    key = key:lower()
    if not Debounce then
        Debounce = true
        if key == 'r' and not Enabled then
            Enabled = true
            ListenToGameEvent.Darkness:InvokeServer(Enum.KeyCode.R,Mouse)
            wait()
            Enabled = false
        end
    end
end)

In server script in StarterCharacterScripts:

local function Dark_Beam(Player, Key, Mouse)
    ButtonDown = true
    Charge = 0
    local bg = Instance.new('BodyGyro')
    local bp = Instance.new('BodyPosition')
    local cBG=bg:Clone()
    cBG.Name='SkillGyro'
    cBG.Parent=Player.Character:FindFirstChild('HumanoidRootPart')
    cBG.D=100
    cBG.maxTorque=Vector3.new(math.huge,math.huge,math.huge)
    local cBP=bp:Clone()
    cBP.Parent=Player.Character:FindFirstChild('HumanoidRootPart')
    cBP.Position=Player.Character.HumanoidRootPart.Position
    cBP.maxForce=Vector3.new(math.huge,math.huge,math.huge)
    local Beam = script.Beam:clone()
    Beam.Parent = Player.Character
    Beam.CFrame = Player.Character.HumanoidRootPart.CFrame*CFrame.new(0,0,-220)*CFrame.Angles(math.rad(-90),math.rad(0),math.rad(0))
    while ButtonDown == true do
        wait()
            Charge = Charge + 1
            local pos=Mouse.hit.p
end
end

The part you need to focus on is

local pos=Mouse.hit.p

It's saying Mouse is a nil value, Mouse is classified in the Local Script and is sent through the Remote Event, But it is saying Mouse is nil for some reason, I'm really confused on this and It'd be great if someone could help, thank you.