The phrase “All your base are belong to us” comes from the video game Zero Wing.
Zero Wing is a science-fiction shoot-’em-up created by Toaplan. The game first appeared in Japanese arcades in 1989, and the meme phrase came from the poorly translated English opening sequence of its European Sega Mega Drive release. In the scene, the antagonist CATS announces, “All your base are belong to us,” using famously ungrammatical English.
The phrase initially circulated as an image and animated GIF on gaming forums in the late 1990s and early 2000s. Its reach expanded after a techno remix, “Invasion of the Gabber Robots,” and an accompanying Flash video spread online. The meme became one of the defining examples of early web humor.
The original Japanese line means roughly that CATS has taken over all the bases; the awkward English wording is the joke’s essential feature. Space Invaders, Galaga and R-Type are also influential space games, but none supplied this phrase.