Defeating Chrono Trigger's Dream Devourer by healing it past 32,767 HP

The Chrono Trigger wiki documents an unusual way to beat Dream Devourer, the game's hardest optional boss: it can be defeated by healing it. The reason is a signed 16-bit integer overflow.

How the trick works

Dream Devourer has 32,000 hit points, a value that sits close to the signed 16-bit limit of 32,767. In the second phase of the fight the boss absorbs every element, so elemental magic no longer damages it — it heals it instead. Cast strong enough magic and its HP climbs past 32,767, the counter wraps around, and the stored value turns negative. According to the wiki, the effect is temporary, but it is enough to end the battle.

What the boss is

Dream Devourer is a special optional boss that appears in the Darkness at the End of Time in Chrono Trigger (DS) and later versions. The story explains that Schala and Lavos passed through an intermediate evolutionary stage before becoming the Time Devourer — the Dream Devourer, able to feed on thoughts, memories and dreams across time. Magus located Schala and tried to free her, but she told him the attempt was futile and that no power could save her; he was sent away and eventually sacrificed his own identity.

The conventional fight

The battle runs in two phases. In the first, the boss counters every physical attack with Mana Reaper, draining MP from a single party member, so strong magic such as Luminaire, Flare or Electrocute is the better option; it can also void status immunity. The second phase begins when it performs an action resembling Lavos Core raising its defence: it then absorbs all elements and answers every attack with Chaos Zone, which inflicts confusion, so non-magical techs are required. Phantasm and The End of All and Nothing deal over 1,000 damage, which makes keeping everyone's HP high a priority. The wiki also lists the ordinary routes to victory: Robo equipped with the Apocalypse Arm and the Dragon's Tear, available after completing Dimensional Vortex, hits for 9,999 and can kill the boss in three or four turns, and an overlevelled Ayla at level 96 reaches a similar result with the Bronze Fist. The overflow is simply another documented option — a rare case of a shipped bug that players can turn into a weapon.