How do you get a living fire block?

How do you get a living fire block? Living Fire Blocks have a 1/50 (2%) chance of being dropped by any enemy killed in the Underworld during Hardmode, including the Wall of Flesh, and drop in stacks of 20–50 at a time.

How do you get fireproof in Terraria? The Obsidian Skin Potion is a buff potion which grants the Obsidian Skin buff when consumed. The buff makes the player immune to lava, Hellstone, Meteorite, and the On Fire!