GJ1214b
GJ1214b is made almost entirely of water. We like to think of Earth as “the blue planet,” but our home is nowhere near as wet as this distant world. Because of how much water is on GJ1214b, its atmosphere is made up of thick steam, and it also likely plays host to weird phenomena like hot ice and something called “superfluid water,” which sounds like it’d be more fun than any water park.