Battle.net

Have 21 Zerg units morphing simultaneously in an Unranked or Ranked game.

Destroy a total of 100 enemy units in Free-for-All Quick Match games.

Score the rank of Gold in all the challenge missions.

Destroy 40 units with a single unit in an Unranked or Ranked game.

Destroy 4 Command Centers, Hatcheries, or Nexuses in an Unranked or Ranked game.