Walk around after boarding the Shinra No. 26 spaceship on disc two. Your party will be able to go down to the space pod or up the ladder to the right to the huge materia. Go to the huge materia and use the talk button at the tall glass to speak with Cid. He will explain the controls in this part of the game. Talk again at the case and enter the password OK [Keypad Enter], Switch [Keypad Delete], Cancel [Keypad Insert], Cancel [Keypad Insert] to collect the Key Item "Huge Materia". After travelling to Cosmo Canyon later in the game, talk to Bugenhagen. He will take your party up to his observatory. Approach to the Blue huge materia and get closer. Your party will receive the Bahamnant ZERO summon materia.