X cannot be assigned to? I just need the part to follow the mouse!

Here is my script, I don't know what is up.

local Player = game.Players.LocalPlayer
local Character = Player.Character
local KeyBind = "u"
local Mouse = Player:GetMouse()

function FollowMouse()
    local Target = script.Target:Clone()
    Target.Parent = Character
    Target.Position.X = Vector3.new(Mouse.X,Target.Position.Y,Target.Position.Z)
end

Mouse.KeyDown:Connect(function(Key)
    if Key == KeyBind then
        FollowMouse()
    end
end)

(Fixed) By redoing the variable to Mouse.hit.p instead of Mouse.x it fixed it!