Trial spawners are found exclusively inside trial chamber structures introduced in Java and Bedrock editions. Unlike normal spawners, they detect all players within a 14-block radius and scale the number of mobs by player count — a solo player faces a total of six mobs while a group of four faces twelve.

Once all active mobs are defeated, the trial spawner ejects loot directly onto the floor for every participating player: a 50% chance of a Trial Key, otherwise bread, cooked chicken, baked potatoes, or regeneration and swiftness potions. The spawner then enters a 30-minute cooldown that keeps ticking even in unloaded chunks. The Trial Key opens a separate Vault block whose richer pool — emeralds, iron equipment, enchanted books — each player can claim once, making group runs more rewarding.

When a player carrying the Bad Omen effect enters a trial chamber, every trial spawner in range converts to its ominous variant: darker particles appear, spawned mobs carry enchanted gear and throw potions, and the associated vault offers rarer rewards. Trial spawners cannot be mined or moved — they drop nothing even with Silk Touch — preserving the challenge structure of every chamber.