Minecraft wiki entry for Phantom, associated text: When idle, phantoms fly around in a roughly circular pattern within 15 to 25 blocks of a player horizontally and within 24 to 35 blocks of a player vertically, leaving a trail of gray smoke while doing so. Their movement speed is one of the fastest of any mob, up to 20 blocks per second. They have a large search radius, targeting and following players from 64 blocks away‌[BE only][more information needed]. Once every 10-20 seconds‌[BE only][more information needed] they swoop down or up quickly to attack. If stopped or hurt during this action, the phantom retreats back to its original elevation. When a path to its original elevation is obstructed by a block, the phantom continues attempting to return to its original elevation until it either attacks or moves out from under the block. Phantoms do not attack an exposed player sleeping in a bed.