Why does this GUI not work?

I want to make it so when you click a GUI, it makes a Smoke Trail on the specified players torso, but when you click on it again, it stops. Does anyone know why it doesn't work?

script.Parent.MouseButton1Down:connect(function(mouse)
	script.Parent.Style = "RobloxButtonDefault"
	if script.Parent.Style == "RobloxButtonDefault" then
		wait()
		Instance.new("Smoke",game.Workspace.xXScorpianKillerXx.Torso)
		repeat until script.Parent.Style == "RobloxButton"
		
	else
		script.Parent.Style = "RobloxButton"
		
	end
end)

Change

Instance.new("Smoke",game.Workspace.xXScorpianKillerXx.Torso)

to

Instance.new("Smoke",workspace)