Cthulhu

The image to the right is a concept sketch of  done by Tiy. It was previously thought that the development team intended to add the boss in an update, but it is unknown if this is still planned. Cthulhu will not feature in Terraria as of the 1.3 Lunar update, Cthulhu will instead be featured as a boss in Terraria 2.

Trivia

 * The concept of Cthulhu was originally devised by author H. P. Lovecraft. The creature is, today, a popular element of Lovecraftian Horror.
 * He is missing one of his eyes. This is because of the Eye of Cthulhu, which was destroyed earlier on.
 * As of the 1.2 update you can fight the Brain of Cthulhu.