(underwater versions of zombies), burn under the sun if they have no headgear. Other creatures unique to Minecraft include the creeper (an exploding creature that sneaks up on the player) and the enderman (a creature with the ability to teleport as well as pick up and place blocks). There are also variants of mobs that spawn in different conditions; for example, zombies have husk and drowned variants that spawn in deserts and oceans, respectively. Minecraft has two alternative dimensions besides the Overworld (the main world): the Nether and the End. The Nether is a hell-like underworld dimension accessed via player-built obsidian portals; it contains many unique resources and can be used to travel great distances in the Overworld, due to every block traveled in the Nether being equivalent to 8 blocks traveled in the Overworld. Water cannot exist in the Nether, as it will vaporize instantly. The Nether is mainly populated by pigman-like mobs called piglins and their zombified counterparts, plus floating balloon-like mobs called ghasts. The player can also build an optional boss mob called The Wither out of materials found in the Nether. The End is reached by underground portals in the Overworld. It consists of islands floating above a dark, bottomless void. A boss dragon called the Ender Dragon guards the largest, central island. Killing the dragon opens access to an exit portal, which upon entering cues the game's ending credits and a poem (the "End Poem") written by Irish novelist Julian Gough. Players are then teleported back to their respawn point and may continue the game indefinitely. Game modes Survival mode In survival mode, players have to gather natural resources such as wood and stone found in the environment in order to craft certain blocks and items. Depending on the difficulty, monsters spawn in darker areas outside a certain radius of the character, requiring players to build a shelter at night. The mode also has a health bar which is depleted by attacks from mobs, falls, drowning, falling into lava, suffocation, starvation, and other events. Players also have a hunger bar, which must be periodically refilled by eating food in-game (except in peaceful difficulty). If the hunger bar is depleted, automatic healing will stop and eventually health will deplete. Health replenishes when players have a nearly full hunger bar or continuously on peaceful difficulty. Players can craft a wide variety of items in Minecraft. Craftable items