Allay

An allay is a small flying passive mob that follows the player who has given it an item, or any note block instrument it has heard in the last 30 seconds. It searches for and collects dropped instances of its held item and drops them near the player or note block it is currently following.

Allays spawn only during world generation, but they can also be duplicated; see § Allay duplication below.

Allays have a 50% chance of spawning in dark oak cages near pillager outposts in groups of 1-3. Allays also have a 50% chance to spawn inside jail cells within woodland mansions in groups of 1-3.