Kingdom Hearts II
Upon realizing the threat of Tron and Sora, the Master Control Program had Sark deploy a special program virus called the Hostile Program. It caused chaos for the computer world as well as the real world in Hollow Bastion. After defeating the Hostile Program, Tron gives Sora the Photon Debugger Keychain.
The Hostile Program is a large, robotic being with a smooth, oval-shaped main body. Its body is indigo and covered in light grey and red computer circuitry, as well as nine conical, red spikes. There is a small opening in the front of its body that exposes its three glowing, yellow eyes, arranged in a triangle pattern, and a silver opening just below this. Its lower body is much smaller and ends in four small, silver appendages. Its lower body is predominantly silver with indigo and red circuitry covering it.
The Hostile Program's arms are not connected to its body and instead hover at its sides. Its arms are translucent, violet tubes with pink spikes in them. The ends are grey and adorned by indigo and red circuitry. Both hands have three pink, squared-off fingers with black and red circuitry on them. Despite its resemblance to the various types of Heartless in Space Paranoids, the Hostile Program is one of the few bosses in Kingdom Heart II that is not a Disney character, Final Fantasy character, Heartless, or Nobody.
The Hostile Program's name reflects its nature as a computer program tasked with eliminating Sora and his companions.