This thing used to be a planet but now it’s not. It is the tallest boulder in the set, and highball possibilities abound, but there are some questionable landings. There are two smaller boulders that sit close to it named Nix and Hydra, which are two of Pluto's moons.

When coming down the approach from Mammoth (Ball of Fame), the first boulder that you come to is Geoff's Boulder. Further to the south (right) of Geoff's, you will see Pluto.