Mechanical Worm

The Mechanical Worm is used to summon The Destroyer (a harder version of the Eater Of Worlds). It can only be used at night; attempting to use it during the day will do nothing and will not consume the item. Unlike Worm Food, it can be used outside of the Corruption. It can be crafted on Mythril Anvil in worlds where the Wall of Flesh has been already killed. Using another Mechanical Worm while The Destroyer is already spawned will result in nothing happening (only rarely) or instant death.

Bugs
Occasionally, The Destroyer will not spawn when the Mechanical Worm is used. This bug exists with all Hardmode bosses and their respective summoning items.