Untouchable

The Untouchable Medal is awarded for killing 25 opponents in a row without dying. It is available in all Multiplayer gametypes. Although this medal is not featured on Bungie's website due to its rare nature, it is assumed to have a Bungie difficulty rating of 10 (out of 10) due to the fact that to kill 20 opponents in a row has a difficulty rating of 9. This medal is very rarely seen and is represented by a 16-sided silver star with a yellow target in the middle. In Halo 2, this medal was called Overkill.