I'm not sure why this fire script is not working ?

Player = script.Parent.Parent
mouse = Player:GetMouse()

function onKeyDown(key)
   key = key:lower()
   if key == "z" then
      x = Instance.new("Part")
      x.BrickColor = BrickColor.new("Bright red")
      x.Size = Vector3.new(10,10,10)
      x.TopSurface = "Smooth"
      x.BottomSurface = "Smooth"
      x.Shape = "Ball"
      x.Tranparency = 0.7
      y = Instance.new("BodyVelocity")
      y.maxForce = Vector3.new(math.huge, math.huge, math.huge)
      y.Velocity = Player.Character.Torso.CFrame.lookVector*80
      x.Parent = game.Workspace
      y.Parent = x
      f = Instance.new("Fire", x)
      f.Size = 12
      f.Heat = 0
      x.Cframe = Player.Character.Torso.CFrame*CFrame.new(0, 0, -12)
      game.Debris:AddItem(x, 6)
   end
end

mouse.KeyDown:connect(onKeyDown)