|The subject of this article was removed from World of Warcraft in patch 4.2.0.
An aggressive pet will attack any mob that enters its aggro radius. In this mode, the pet will be constantly starting fights with mobs in its vicinity. This may be useful to a hunter or warlock who wants to grind a lot of monsters, or in certain PvP situations, but it can be very detrimental even while soloing, but especially in an instance, where drawing the attention of a swarm of monsters can quickly wipe out a party. In an instance, all pets are expected to be passive and remain so. The master of the pet is expected to command the pet to do exactly what he wants it to do, so that it doesn't pull unintended clusters.
Pets on aggressive could be used to help low-level players level in dungeons while the high-level player, who had to own the pet, was AFK. The high-level player would put the pet on aggressive and start automatically following one of the low-level players, who would lead the way while the pet killed mobs. If it was desired to loot or skin mobs, the looting mode would be set on Free-for-All and a low-level player would loot.
In Patch 4.2, Aggressive became "Assist."