Ender Crystals are special items found in the game Minecraft. They are used to heal the Ender Dragon, a powerful boss that players can encounter in the End dimension. When the dragon is damaged, it can regenerate health by absorbing energy from these crystals. These crystals are located on top of Obsidian pillars in the End. Players must destroy the crystals to prevent the dragon from healing. Once destroyed, the crystals explode, dealing damage to nearby players and mobs. This makes them a crucial target during the battle against the Ender Dragon.