Halley's Comet

Halley's Comet is a comet that is seen on Earth every 75.3 Earth years. It is full of ice. Because it is full of ice, it is cold like Mars' ice caps. Humans visit Halley's Comet to get ice to dump into the sea on Earth.

During the episode A Taste of Freedom, it is revealed that a battle was fought over Halley's Comet. During the battle, Old Man Waterfall lost his hand planting Earth's flag, "Old Freebie."