The Showstopper medal is a Halo: Reach and Halo 4 multiplayer medal. Appearing as an octagon with an image of a Combat knife crossed out in a "No" symbol. It is awarded to a player who kills an opponent while the latter is performing an Assassination on a teammate. It was revealed alongside two other medals in the Bungie Weekly update 07/09/10.
- In order to get this medal, one must kill the opponent BEFORE the combat knife/Energy Dagger/Energy Sword is inserted into the victim or before the animation is done.
- It is possible to receive the medal by yourself, without having the need of another player to help, by probable uses of lag or having enough health or being far enough to survive a nearby grenade you've thrown yourself where the assassin won't.