The Crushing Hyphalumps in the first room are immune to damage until all other mobs have been defeated. Additionally, they leave behind a poison trail after moving. Starting your turn on the poison trail is instant death. Positioners going last is helpful with saving people who misposition
The boss occasionally summons a Leaping Coprinus (summon) that has all the abilities of a normal Coprinus. When the add dies within 2 cells of the boss, Sugnuf becomes vulnerable to damage for 2 turns. The boss will cast Sleazy Gro which deals air damage and inflicts - 2 range and another spell which deals damage and push targets back 2 cells. Always keep empty cells around you so you don't get stuck on a poison trail.
Phase 2 begins when the boss reaches 1 percent health. He will summon adds on his turn and will become invulnerable for 3 turns. Stay alive and focus on dispatching the adds until the boss becomes vulnerable again. After 2 turns, the boss becomes vulnerable again and can be killed.