The headache following playing a video game for a long amount of time. This originates from the game Assassin's Creed II
in which the main character is put into a machine called the Animus which allows him to relive the memories of ancestors and towards the end of the game, experiences some side effects such as headaches and hallucinations.
Guy 1: Hey wanna go to a party tonight
Guy 2: Sorry dude, i just spent 8 hours straight playing MW2
and have the worst animus headache.