Minecraft wiki entry for Ender_Dragon, associated text: The /summon ender_dragon command, by default, summons a harmless Ender dragon that hovers in place ‌[JE only]. Setting the DragonPhase tag (by issuing either the /summon ender_dragon ~ ~ ~ {DragonPhase:0} or the /data merge entity <selector> {DragonPhase:0} commands) starts the Ender dragon's ordinary behavior, although the health bar does not appear because it is managed by the End's dragon fight status rather than by the dragon entity herself ‌[JE only]. If spawned away from the center of the map (x=0, z=0), she flies to the center then resumes normal behavior (see #Behavior).