1st u need rhyperior
2nd u need 2b in a duble battle
3rd u need rhyperior 2 b the last pkmn u use (so while ur battling rhyperior is the only 1 that hasnt fainted yet)
4th it needs the move rock trow
ok so ur in the duble battle and rhyperior is the only 1 left now use rock throw on ur enemy and a geodude may apear rite next 2 it
so its thrown a geodude thinking it was a rock and then itll battle with ya
(its at lvl 40 so make sure they rnt that tuff) and its moves rnt bad (take down, rock polish, rollout and iron defence)

Cammo waz ere!