The Rat Pack

This achievement requires all 5 party members to be mounted simultaneously, so it cannot be completed solo. Assemble a full group of 5 players before entering Karazhan.

Clear Karazhan up to and including The Curator, as the Rodents of Usual Size are located on the path beyond The Curator's room.

After passing through the portal past The Curator, find and loot all five Rodents of Usual Size as clickable critter-like NPCs. Two are right past the portal after The Curator, one is down the ramp near the first Fel Draenei caster, one is to the right down another ramp past another Draenei caster, and the last is right before the Shade of Medivh. If any are accidentally killed, soft-resetting the instance will respawn them, but they disappear if you leave Karazhan entirely.

Each player must use their Rodent of Usual Size item before entering combat with the Mana Devourer. Do not shapeshift, use leap abilities such as Infernal Strike, or switch specializations, as these will despawn your mount. Beast Mastery Hunters cannot use their pet while mounted on the Rodent, so switching to a different specialization is not an option — consider playing a different spec entirely for this attempt.

With all 5 party members mounted on their Rodents of Usual Size, defeat the Mana Devourer to complete the achievement.