Quadratus

"Thy next foe is... In the seaside cave... It moves slowly... Raise thy courage to defeat it."

- Dormin

The Second Colossus, nicknamed Quadratus, is a major antagonist from the video game Shadow of the Colossus. It is the second boss encountered in the game and a vessel for the essence of Dormin.

Past
Quadratus, along with the other sixteen Colossi, were created by Lord Emon to contain the fragmented essence of the defeated evil Dormin. He set them all to wander the Forbidden Lands, destroying anyone that comes their way, so that Dormin could never be resurrected.

Shadow of the Colossus
When a young man named Wander trespasses in the Forbidden Lands and asks the disembodied spirit of Dormin to resurrect his deceased lover Mono, Dormin agrees under the condition that Wander kill all sixteen colossi (tricking Wander into releasing his essence so he may be reborn). Wander agrees, and sets off.

Quadratus is the second colossus he encounters, hiding in a seaside cave underneath the bridge. It will burst out of the cave when it sees Wander come near and attack him, attempting to step on him. Wander must shoot the bottom of its feet when it rises up to stomp on him, causing Quadratus to fall over and allow Wander access to its back. He must then make his way to the vitals on Quadratus' back and head (and left side in Hard mode) and stab them, all while Quadratus is trying to shake him off. Once all vitals have been stabbed, Quadratus will die, collapsing to the ground and releasing the fragmented essence of Dormin contained within its body.

This fragmental part of Dormin will bring Wander back to the Shrine of Worship, where he will be prepared to face his next foe. It will later combine with the other fifteen parts to form Dormin, who will posses Wander and later be banished by Lord Emon.

Quadratus' corpse can be seen as the credits roll.

Trivia

 * Quadratus appeared as a costume in the Shadow of the Colossus pack for the game Little Big Planet 3.