Spaceships flips Asteroids: you're the asteroid, hunting the ships
Spaceships (Reverse Asteroid)

A browser game that inverts the classic arcade formula: instead of piloting a ship and dodging asteroids, you control the asteroid and smash the spaceships. The Hacker News thread praises the twist, with players noting the challenge of tracking multiple ships and requesting difficulty ramps, color coding, and arrow-key support. One commenter even built a first-person Asteroids variant.
Unlike regular asteroids where you can keep track of your ship because you only have to follow one object around the screen and you control it, it seems like the hardest part of this game is finding the ships, especially when they start to be multiple shapes.