Win 3 Team Unranked or Ranked games in a row.
Kill a Stank before it kills anything on Hard difficulty.
Score the rank of Gold in the “Tactical Command” challenge mission.
Finished a season in the Top 50 of a Team Diamond Division.
Survive 15 Infested Horde Attacks in the “Night 2 Die" mode of the “Left 2 Die” scenario.