Minecraft wiki entry for Combat, associated text: Withers are boss mobs that can be summoned by making a "T" shape with soul sand and placing 3 wither skeleton skulls on top. They have 150 hearts of health (300 in Bedrock Edition) and shoot black or blue skulls that give the Wither effect and do as much damage as a ghast fireball, the blue skulls are also able to destroy any block except bedrock, barriers and end portal frames. So when spawning the wither make sure the player is in a confined space (made with obsidian if being done in survival) with lots of effective potions drank to kill the wither quicker. Upon summoning one, drink a potion of Strength, a potion of Regeneration, a potion of Swiftness, and maybe put a totem of undying in your off-hand. When the wither has gotten up to max HP in a few seconds the Wither will gain health and cause a massive explosion. A good thing to do is to shoot it with arrows until down to 75 hearts of health and then kill it quickly with a sword to end the battle. In Bedrock Edition, after the wither's health reaches 150 hearts (half health), it will explode again and spawn 4 wither skeletons, then the wither can use dash attacks, which can be dangerous. The wither drops 1 nether star which can be used to make a beacon. Enchanted diamond or netherite swords especially smite and diamond or netherite armor is recommended.