Why doesn't the "Wood" go to the player's mouse's position?

I have no errors in this script. And it works fine, except the "Wood" doesn't go to the mouses target. Script:

player = game.Players.LocalPlayer
mouse = player:GetMouse()
script.Parent.Selected:connect(function(build)
    l = Instance.new("Part", workspace)
    l.Name = "Wood"
    l.TopSurface = "Smooth"
    l.BottomSurface = "Smooth"
    l.Anchored = true
    l.Transparency = 0.4
    l.BrickColor = BrickColor.new("Brown")
    l.CFrame = CFrame.new(Vector3.new(l.Position, mouse.Target))
end)