The Open Season medal resembles three green and gold slugs sitting on top of a five pointed bronze star; it is awarded to individuals after killing 10 opponents in a row without dying with a shotgun on multiplayer matchmaking, in Firefight, and in Campaign in Halo: Reach. Melees with the shotgun do not count toward the medal. The Open Season medal is the last of the shotgun spree medals in Halo 3 & Halo 3: ODST, and the second of the shotgun spree medals in Halo: Reach. This medal can be awarded on any gametype containing a shotgun.
- The easiest playlist to earn the Open Season medal is Living Dead as all the opponents wield energy swords requiring them to come into close range to infect the individual. This allows players to kill the zombies with reletive ease with a shotgun, given to all humans, as they stream through to infect the player.