Killer
From Create Your Own Story
Rain.
It falls from the sky.
It is considered helpful for many reasons. Ending a drought, for example.
The best part about it is that no one can see your tears. Especially useful as you hold the corpse of your girlfriend in your hands. You had planned on proposing today; that all changed as she was shot. The killer got away.
But you now know what you must do. It is time to kill the killer. It is time you get revenge. Or you can let the cops handle it. But that's boring as fuck. Just get the gun out. Give in.
The police are waiting for you. Let the games begin.