Fungalophobia

This achievement is only available during the Therazane daily quest version of Glop, Son of Glop — not the original quest. You must personally start the quest dialogue with the Troll yourself; if someone else in your party initiates it, you may still qualify, but initiating it yourself guarantees eligibility.

During the fight, Fungalmancer Glop throws Boomshrooms at your current position roughly every 2 seconds; these tiny mushrooms on the ground explode after about 5 seconds. Stay at range and keep moving to avoid them — running away from the shrooms is more reliable than trying to kill them, as they despawn on their own. Damage absorbed by shields such as Ice Barrier counts as avoiding damage for the achievement, so absorbing hits still qualifies.

Avoid meleeing Fungalmancer Glop heavily and rely on ranged abilities instead, since staying at range naturally keeps you clear of freshly thrown Boomshrooms. Pets and minions such as Hunter pets or Death Knight minions can be hit by Boomshroom explosions without invalidating the achievement.

The achievement does not trigger immediately when Fungalmancer Glop dies — it only appears when you turn in the Glop, Son of Glop daily quest.