Summoning the Wither requires you to first have three Wither Skeleton heads, which are a random and rare drop from Wither Skeletons, most commonly found in Nether fortresses. Using a Looting III ...

Since the launch of Minecraft, the Nether dimension remained a barren wasteland until 2020 when Mojang revamped the entire hellish dimension by releasing the 1.16 Nether Update.