Overloader

 is a Hardmode Mini-boss that can fought after defeating Wall of Flesh. Upon defeat will drop a Tectonic Key used to open chests in the Underworld Domain and the Tectonic Cage.

Spawn
The Overloader is summoned by dropping Worm Wood into any source of Lava in the Underworld. Awakening two Overloaders.

Behavior

 * The Overloaders will arrive from the bottom corners of the corner and burrows towards the player.

Attacks

 * The Overloader will charge towards the player from below and burrow back down.

Bugs

 * Sometimes the second Overloader head will detach from its body when summoned causing the battle to be a little harder as you will have to keep track of 3 points of attackers.