Pegasus' KaibaCorp takeover attempt
He planned to achieve this through dealings with large shareholders of KaibaCorp, The Big Five, and their ruthless business techniques, while KaibaCorp had a low reputation and then rebuild its reputation with him in charge.
Pegasus had established himself as a genius game designer when he created Duel Monsters, but his company, Industrial Illusions, alone was not enough to market the game at its full potential, so he teamed up with KaibaCorp to develop projections of the cards to make the game more lifelike. This was done with the Solid Vision, Seto Kaiba created.
With intentions of taking over the company, Pegasus had spies work for KaibaCorp. Among them were Kemo and another guard. They were trusted with information confidential to the company, which they passed on to Pegasus.
KaibaCorp had a good reputation due to its president, Seto Kaiba, being the number one gamer in Japan. However when Kaiba lost a Duel to Yugi Muto and his other self, Yami Yugi, their reputation dropped as investors lost confidence in them. In the manga, Kaiba was also left in a coma due to his Penalty Game.
In the manga, while Kaiba was out of action, The Big Five possessed 60% of KaibaCorp's shares and controlled its decision making. They made a deal with Pegasus, which would result in Pegasus becoming the chief executive. The deal was made under the condition that Pegasus would defeat Yugi in an official Duel in order to rebuild the company's reputation afterwards.
Pegasus set up the Duelist Kingdom tournament as a means of facing Yugi in a Duel. He sent Yugi an invitation to the tournament and faced him in a Duel though a TV using a videotape. Pegasus won this Duel and for Yami Yugi's Penalty Game, he removed the soul of Yugi's grandfather, Solomon Muto, from his body. He forced Yugi to enter the tournament, as it was the only way of retrieving Solomon's soul.
The Big Five broke into Kaiba Manor to try and steal important documents. However Mokuba Kaiba realized what they were doing and swallowed the key to the safe in front of them. Unable to immediately retrieve the key, The Big Five brought Mokuba to Pegasus Castle on Duelist Kingdom, where he was held prisoner until they could retrieve the key from him.
Eventually, Seto awoke from his coma, and made it to Duelist Kingdom, where he confronted Pegasus. Seto lost the duel against Pegasus, and his soul trapped in the Soul Prison card. Mokuba also had his soul removed, and a 3D scan had been made on his body, thus retrieving the key's structure, allowing a copy to be made. During the finals of the tournament, Yugi and his dark counterpart managed to defeat Pegasus, thus turning the entire takeover attempt into a failure.
In Yu-Gi-Oh! R , after Pegasus died at the hands of Dark Bakura, his protege Yako Tenma attempted a second takeover of KaibaCorp to further his Project R.A. to revive Pegasus, but it also ended in failure.