Love Machine is a sadistic, murderous, and diabolical digital entity, and the main antagonist of the 2009 animated Japanese film, Summer Wars. It is an artificial intelligence program that obtains more strength through the consumption of other avatars, and seeks to gain total control.
Kenji Koiso is a moderator of OZ, a massive virtual reality program, who is invited to the home of a friend Natsuki to celebrate her great grandmother Sakae's birthday. He receives a mathematical code in an email and cracks it, unleashing a malignant Artifical Intelligence called Love Machine. The AI hacks into Kenji's account and uses his avatar to wreck havoc on OZ's infrastructure. It is confronted by King Kazuma, the rabbit avatar of Natsuki's cousin Kazuma. Love Machine devours some unfortunate avatars and, in its new and bigger state, defeats King Kazuma in battle. It then attacks and gobbles up more avatars to increase its growth and power, hacking into other accounts. Love Machine causes more drastic effects in the real world by creating traffic congestion and interfering with electric devices.
For a time, OZ is restored while the truth of Love Machine is revealed. It had been created by Natsuki's relative Wabisuke as a test run program and was sold to the United States military. Love Machine ultimately kills Sakae by cutting off her heart monitor, thus leaving her to die without anyone finding out before it is too late. Determined to defeat Love Machine, Kenji and Natsuki's family bring together a supercomputer cooled by blocks of ice. They manage to capture Love Machine but are thrown off when the supercomputer overheats, allowing Love Machine to engulf King Kazuma and gain more power. Using its power, Love Machine directs a satellite with the intent of crashing it into a nuclear plant.
Finding out that Love Machine sees everything as a game, Natsuki confronts the AI in Koi-Koi rounds. While initially winning, Natsuki almost loses her winnings with the wagered accounts put up against Love Machine. Fortunately, OZ users all over the world put forth their support, giving Natsuki the chance to devastate Love Machine. Unfortunately, a spiteful Love Machine redirects the satellite to crash into their home. Wabisuke counters his creation by disabling its defenses, permitting King Kazuma to reconstitute. King Kazuma is led by several of the family's avatars and attacks Love Machine with a punch to the face, destroying it. Kenji manages to redirect the satellite from crashing into the estate (although its collision causes a geyser to erupt).
Wabiskue describes Love Machine as an AI with a desire to learn. Love Machine sees everything as a game and plays them out like a game, devastating opponents and being swayed into other contests, such as the Koi-Koi rounds against Natsuki. It also gains power by consuming other avatars, becoming a far larger and more intimidating force.