STOP! Ping
I don't know is somebody already suggested this idea, I think it would be a good one.
But why and when should we use it? We could use this ping to signal to a greedy person to STOP chasing a singed or towerdiving a shen, for exemple. Another use of this amazing ping would be to signal to the "leashers" to return to lane, because it's so annoying when someone steal your buff.
*sorry for my english, I'm french