Take a Sandshrew, and name it Xcav8r (Excavator). Xcav8r loves to dig. You must teach him Dig as soon as possible after you catch him. He is also very competitive, and wants to prove he is the best digger. He must fight against every trainer-owned ground-type you come across (that does not conflict wit an existing solo) without switching out, and use Dig as his only damaging move in all battles he takes part in, unless under certain conditions. If he it hit while underground, or is in any way prevented from using Dig (run out of PP, torment etc.), he will throw a tantrum, and will only use either Earthquake or Magnitude until he either defeats the opponent Pokemon currently in battle, or faints himself. Xcav8r has a huge rivalry with the Drillbur family, and as such, must solo Clay. Upon doing so, Xcav8r may evolve. Upon evolution, he gains the ability to control his emotions, and therefore does not throw tantrums anymore. He also may use damaging moves other than Dig/Magnitude/Earthquake. He must use Dig as soon as he enters battle, though, and may not use any other ground-type moves unless he is hit while underground. He also no longer needs to battle every ground-type. He also wants to prove his victory against Clay's Excadrill was not a fluke, so, knowing Excadrill was an Uber in gen 5, Xcav8r decides to defeat an uber to show his greatness. Xcav8r must solo White Kyurem.
Good luck!