Why doesn't this script get the mouse position properly?

When It fires the part goes way above the mouse position. like this: https://i.gyazo.com/72dda5e96fed58841365f4e803810587.gif

However it works perfectly in Studio Testing. The Remote Event fires when a key down (Create) and key up (Fire).

Mouse is Mouse.Hit

My discord: Prismous#1646

local DiscCharging
local events1= Instance.new("RemoteEvent")
events1.Name = "DestructoDiscEvent"
events1.Parent = game.ReplicatedStorage.RemoteEvents.Skills
events1.OnServerEvent:connect(function(plr,Statis,Mouse)
    Player = plr
    local FormMultiplier = plr.Gamestuff.Characters.Folder.FormMultiplier.Value
    local Damage = SaiyanModule.damage(plr, 15,FormMultiplier)
    print(Damage)
    if Statis == "Create" then
      local Disc= Instance.new("Part",plr.Character)
      Disc.Name = "Disc"
      Disc.BrickColor = BrickColor.new("Cool yellow")
      Disc.Material = "Neon"
      Disc.TopSurface = "Smooth"
      Disc.BottomSurface = "Smooth"
      Disc.FormFactor = "Custom"
      Disc.Size = Vector3.new(0.2, 3.12, 7.44)
      Disc.Transparency = 0.2
      Disc.Anchored = false
      Disc.CanCollide = false
      Disc.CFrame = plr.Character.LeftUpperArm.CFrame * CFrame.new(0, 0, 0)--* CFrame.new(0,-4, 0)* CFrame.Angles(0, 0, -math.rad(90)) --* CFrame.new(0, 0, 0)
      local CylinderMesh = Instance.new("SpecialMesh")
      CylinderMesh.Name = "CylinderMesh"
      CylinderMesh.MeshType = "Cylinder"
      CylinderMesh.Parent = Disc
      CylinderMesh.Scale = Vector3.new(0.2, 1.1, 1.1)
      local Weld = Instance.new("Weld")
      Weld.Parent = Disc    
      Weld.Part0 =    Disc
      Weld.Part1 =  plr.Character.LeftHand
      Weld.C0 = CFrame.new(1, 0, 0) * CFrame.Angles(0, 0, -math.rad(90))
      DiscCharging = true
       Rotate = true
        plr.Character.HumanoidRootPart.Anchored = true
       plr.Character.RotatePlayer.Disabled = false
      biggerdisc(plr,CylinderMesh,Mouse)
    elseif Statis == "Fire" then
        local Weld = Player.Character. Disc.Weld
        local CylinderMesh = Player.Character. Disc.CylinderMesh
        local Disc = Player.Character. Disc
        Weld:Destroy()
       plr.Character.RotatePlayer.Disabled = true
        plr.Character.HumanoidRootPart.Anchored = false
        DiscCharging = false
    wait(0.001)
      local bv = Instance.new("BodyVelocity")
      bv.velocity = CFrame.new(Disc.Position, Mouse.p).lookVector*80
      bv.maxForce = Vector3.new(math.huge, math.huge, math.huge)
      bv.Parent = CylinderMesh.Parent
      game:GetService("Debris"):AddItem(CylinderMesh.Parent, 4)
      local debounce = false
      CylinderMesh.Parent.Touched:connect(function(hit)
        if debounce == true then return end
        debounce = true
        if hit.Parent:FindFirstChild("Humanoid") and hit.Parent:FindFirstChild("NPC") == nil and hit.Parent.Name ~= plr.Name  then
            hit.Parent.Humanoid.Health = hit.Parent.Humanoid.Health  - Damage
            DamageTakerGUI(plr,hit,Damage)
        end
        wait(1)
        debounce = false
    end)
    end
end)

function biggerdisc(Player,Cylinder,Mouse)
    while DiscCharging and Cylinder.Scale.Y <= 2 and wait() do
         for i = 1,5 do
            Cylinder.Scale = Cylinder.Scale + Vector3.new(0,.005,0)
            wait()
         end
        wait()
    end
end