Overkill

Were you looking for the Halo 2 medal with the same name?

The Overkill medal (also called Killtacular in Halo: Combat Evolved and Halo 2) is awarded for killing four opponents within four seconds of each other in standard multiplayer games (and Halo: Spartan Assault) and within less time in campaign and Firefight. In Halo 4 multiplayer and Spartan Ops, the kills need only be within 4.5 seconds of each other.

Originally, the medal was represented by 4 green stars in a bronze circle. In Halo 4 it represented by four white stars on a forest green circle rimmed with green and brown. The medal is monochrome and imposed on a shield in Halo: Spartan Assault and Halo: Spartan Strike. Receiving this medal results in the announcer shouting "Overkill!" to the player.

Trivia

 * In Halo 2 the medal is called a "Killtacular." Earning the medal in a Halo 2 for Windows Vista multiplayer game will unlock the Killtacular achievement.
 * Earning this medal in a ranked free-for-all Halo 3 matchmaking match will unlock the Overkill achievement, as well as the Commando harness helmet and Ascetic harness shoulders.
 * An easy way to get this medal is in Grifball, which is played in close quarters with Gravity Hammers and Energy Swords. Thus, kills are very easy to get, especially if the player spawn kills.