Mechanical Worm

The Mechanical Worm is a Hardmode item used to summon The Destroyer, the Hardmode version of the Eater of Worlds. It can only be used during night time; attempting to use it during the day will not summon the boss nor will it consume the item. Using another Mechanical Worm while The Destroyer is already summoned, again, will result in the Mechanical Worm not being consumed, and a second Destroyer will not appear. If you have not defeated The Destroyer yet and you are in Hardmode, all enemies have a 1 in 2500 (0.04%) chance of dropping this item, with the exception of statue-spawned enemies and Meteor Heads.

History
Mechanischer Wurm 机械蠕虫