The Gigantic Box is a magical box. It takes a single person almost 3 hours to open it with a dagger in two hands.
The Gigantic Box is immune to all magical damage (except Spiritmasters' energies) and will only take 1 damage from all physical regardless of a crit strike. Assassins and SMs are the best classes to kill the box solo. Assassins, with their fast damage and two weapons, can whittle the 12,000 hp down within a few hours by themselves. The Spiritmaster can utilize their spirit energies and a pet to do additional damage. All dots will be resisted. If you have a slow attack weapon, you are better off removing it and fighting this box with your bare hands. Then, you will get 2 hits in around the same time as your normal attack. You only get 1 total damage per attack. A three strike weapon will not be able to do 3 damage per swing.