The telltale condition of a computer game that has so many pixelated graphics that you think the game is ill. Originally found in polish computer game magazines in the early 90's, either Top Secret or the early Secret Service, describing antiquated graphics in DOS era 3D FPS games. When you'd walk up to a wall, the texture texels would become huge, and show mad pixelation.
This game has mad pixelosis!
Your momma's so ugly, she has pixelosis.
Hexen looks so bad, I think it has pixelosis.
Doom2 has pixelosis.