Unbound minion

From Guild Wars Wiki

Unbound minions are minions that attack everything within its aggro zone. This occurs when the character that animated the minions is killed, in which case, all the minions that the character controlled become hostile. Unbound minions will attack both friend and foe, and anyone can attack it.

Sometimes in PvP, it is a common tactic to wipe out the opposing team's Minion Master, especially if it can be done while the minions are near the enemy resurrection shrine or base. This is especially useful in the factions repeatable mission Fort Aspenwood where Minion Masters are commonly used by the Kurzicks.