Trial Spawner is a unique spawner found exclusively in trial chambers. It spawns mobs in waves, scaling in difficulty based on the number of nearby players, and goes inactive for 30 minutes after all spawned mobs are defeated. It cannot be obtained in Survival mode or moved by a piston.

Trial Spawners activate when a Survival or Adventure mode player comes within 14 blocks and has a direct line of sight. Once triggered, they spawn mobs every 2 seconds, up to a limit based on player count. Each additional player increases the number of simultaneous and total spawned mobs. Unlike regular spawners, they ignore light levels and require line-of-sight for spawning.

When all spawned mobs are defeated, the spawner rewards each player with consumable items or a Trial Key, then enters a 30-minute cooldown. Spawners placed by players function like naturally generated ones. If a player with Bad Omen enters its range, it converts into an Ominous Trial Spawner, increasing difficulty and skipping any cooldown.