Worm Food

It only works while you are standing inside Corruption, surface or underground, and the hour does not matter. The usual mistake is trying to summon at the edge of the biome and getting nothing back, so wait until the background and the music have actually flipped over before you spend one.

The item does not care which evil your world generated with. Plant enough corrupt blocks in one place for the game to count it as a biome and the summon works there, which is how people collect the drops in a Crimson world without visiting anyone else's map.

Fight it in a wide flat space or a long tunnel you dug yourself. Every segment you break splits the body in two, and a cramped natural chasm turns one worm into a dozen closing in from angles you cannot see coming.