scmJS docs

Kill Unit

Kills every unit of the type the player owns, anywhere on the map. They die as they would in a fight, with their death animation, and add to the player's death count.

Action 22 · Kill Unit(Player, Unit);

Argument Takes Stored in the action
Player a player or group bytes 16–19
Unit a unit type, or one of the unit classes bytes 24–25
Kill Unit("Player 8", "Zerg Larva");