Catalyst

Catalyst is an uncommon Silent skill that doubles the current Poison stacks on an enemy and Exhausts for 1 Energy. If the enemy has 10 Poison, Catalyst brings it to 20; if it has 20, it becomes 40. Since Poison deals damage equal to its stack count each turn, doubling stacks effectively doubles all future Poison damage from that point. It's an exponential multiplier on an already strong damage-over-time system.

Catalyst is the centerpiece of many Poison builds, turning modest Poison stacks into game-ending totals. The ideal play is to accumulate 15-20 Poison stacks via Deadly Poison and Noxious Fumes, then use Catalyst to explode those stacks into 30-40, which will deal hundreds of total damage over the remaining turns. Upgraded, it triples the Poison instead of doubling — turning 10 Poison into 30 or 20 into 60. A single upgraded Catalyst with reasonable Poison setup can kill any boss in the game outright within 1-2 turns.