Phantom

Phantoms are flying undead hostile mobs that spawn in the night sky when the player has not slept in a bed or died for at least 3 in-game days. They attack by diving at the player from the sky to bite them.

Phantoms spawn unless the game rule spawn_phantoms‌[JE only] or doInsomnia‌[BE only] is set to false. The spawning mechanics differ between Java and Bedrock editions. In both editions, they spawn in the Overworld above a player whose "Time Since Last Rest" statistic is at least 1 hour (72000 ticks or 3 in-game days).[verify] This statistic is reset when the player dies or enters a bed. This does not require skipping the night. Furthermore, the player must not have a block overhead that blocks light in any way; for example, leaves prevent phantoms from spawning as they have a light opacity of 2, but glass does not, as its light opacity is 0. Cherry planks work because they cannot be seen through. Phantoms do not spawn above players in Spectator mode, but they do spawn above players in Creative mode.[2]

Phantom spawning is similar to other monsters spawning: the spawn location must have a light level of 7 or less, and spawns are limited by the monster population cap. Phantoms are also subject to a density cap of 5. Phantom spawn attempts are made on surface blocks throughout the same spawn radius as other monsters. However, when a phantom spawn attempt succeeds, the phantom appears somewhere in a 21×15×21 cube centered 28 blocks above the player instead of at the block where the spawn attempt occurred.