13. Three-4b
Considered one of the largest planets ever discovered, it has such a low density that its surface is considered "fluffy" and looks like a cork.
14. Ogle-2005-Blg-390lb
One of the coldest planets in the universe, with a surface temperature of -220 °C.
15. Karplanst-438b
This is the most Earth-like planet in terms of mass. Even though it is a planet with twice the amount of oxygen as Earth, its surface could be habitable by monstrous insects.
17. Three-2b
Considered the darkest planet ever known, it reflects less than 1% of the light that reaches its surface.
18. HD 106906
This planet orbits a star located about 96 billion kilometers away – and no one yet knows how it formed.
19. Kepler-78b
Located less than 900,000 kilometers from the star it orbits, this planet is believed to be covered in lava.
20. 2mass J2126-8140
This planet is so far from its star that scientists still don't understand how it stays in orbit.