Is Player Ally variable. This variable allows the players to set the allegiance of a monster. Do note however, that only the Human Grunt, Alien Slave and Alien Grunt have new skins to show that they are friendly. The friendly monsters will attack any monster not friendly to the player, and act like a friendly to all player Allies. This is a powerful effect and for example will allow the mapper to place friendly Grunts guarding a scientist from other grunts and monsters.
Players lose points for killing friendly monsters.
Please note that Barneys can be set to attack the players on sight. You MUST make sure that the first monster spawned after the server starts is NOT friendly. To avoid the problem, simply ascertain that a normal monster enters the map before any friendly monsters. This is the Uzi, a new weapon in SvenCo-op v1.9. This unique entity allows mappers to set up random events, monster spawns, etc.