Lunatic Fringe was a module for
After Dark, the
screen saver for the
Macintosh, before the screen saver was built-in to
MacOS. It was notable because it was actually a playable game, and a pretty good one. You played with the keyboard, but if you accidentally bumped the mouse while playing, it would end the game and drop out of screen saver mode.
The goal was to fly around in your goofy little spaceship blasting other, different spaceships. Pretty simple, but the graphics were kinda cool for its time. (around 1994) It's the sort of rendered sprite graphics you see in Ambrosia software games like Swoop and Escape Velocity. There were also asteroids around, and you had a large space to explore.
Lunatic Fringe inspired similar games like Asterax, Space Madness and the hugely popular Maelstrom. I believe Space Madness was most similar in play to Lunatic Fringe, but my memory is fuzzy...