Frankenstein

The Frankenstein is a Hardmode enemy that spawns only during a Solar Eclipse, during which they are as common as zombies. Hitting much harder, having more life and walking faster, they can be considered "super-zombies".

They are one of only two (the other being Swamp Thing) enemies that drop the Broken Hero Sword, which is necessary for crafting the most powerful sword in the game.

Trivia

 * Terraria continues a common mistake about Frankenstein. Frankenstein is the name of the doctor who created the monster, not the monster itself. The monster is referred to as the Creature throughout the original novel.