Toxicity Strike Team

After the first boss go up the stairs to the left instead of straight through the new open door. Keep going until you get to the room Intake Resevoirs. To the left there is a pool with a titan machine in it and at the bottom of the pool you'll find a button. If you push that button you will spawn the Toxic Swogmother. Kill her for the achievement.

Easy Solo for Level 80-100 Worldsoul Saga & Beyond...

1. Mythic Difficulty.

2. Head to Intake Reservoirs on the right side of the dungeon map, after the first boss.

3. Jump in the pool of water with the spinning thing, head to the east side and swim down, push the little red button on the wall.

4. Swim on up and get out of the pool asap.

5. You'll notice Toxic Swogmother has spawned where you entered the room.

6. Defeat the Toxic Swogmother.

7. ?

8. Profit. Achievement Completed.

Criteria:
Defeat the Toxic Swogmother after Purging the Water Intakes in Halls of Infusion on Mythic difficulty.

Strategy:
After defeating the first boss, there will be a pathway to the left. Eliminate a few mobs on your way to the Intake Reservoir room. Once inside, there is a machine with a button. Press the button, and this will spawn the Toxic Swogmother. Defeat her, and you win!