Polyphemus

Polyphemus was an extrasolar asteroid that penetrated the Solar System sometime during the 1900s.

It remained undetected, due to its distance from Earth, until the 1990s when it began to approach Jupiter. It unexpectedly crashed into one of Jupiter's moons - the 1986VG1 Ulysses. Ulysses and Polyphemus were both separated into thousands of smaller meteors that were launched into a trajectory which would collide with Earth in mid-1999.

The Stonehenge Turret Network was created to combat the meteors and protect the planet, but most of the meteors crashed regardless. This event was later known as the Ulysses Disaster.