Shimmer 44

We return to our heroes battling a pack of regenerating, multi-headed trolls deep beneath the Ladikor mountains. From the darkness, an ominous voice booms: “Who has disturbed my slumber?” A skeletal blue dragon emerges from the far side of the room and takes flight. “Behold, Reticularus! Fly in the face of my magnificence!” The dragon assaults the party with lightning breath, tail swipes, and wing buffets, while swirling clouds of blinding sand whip through the chamber.

Despite multiple Mass Cure Wounds from Falorn, the heroes struggle to survive. Reticularus bites Falorn unconscious, though Tuesday quickly revives him. Meanwhile, the resurgent trolls overwhelm Caper and knock Goram unconscious. Dirk conjures a Wall of Fire that engulfs the three remaining low-health trolls, dropping them unconscious and ending their regeneration. With his minions fallen, Reticularus declares that he will consume the heroes himself.

D&D Mechanics: Troll Regeneration

One-Tap Model: Taking 1+ point of the required damage type turns off the troll's 10 HP regeneration for its next turn, and it dies if it starts its turn at 0 HP without regenerating. Because the "disable" trigger can happen on the exact same hit that drops it to 0 HP, a fatal Fireball (or fatal Magic Missile) is a true one-tap kill.

Two-Tap Model: Taking the required damage type while standing only halves regeneration (from 10 HP down to 5 HP) rather than disabling it. To permanently kill the troll, it must first be reduced to 0 HP (Tap 1) and then take 10+ Acid or Fire damage in a single hit while already at 0 HP (Tap 2).