Suppose Pokemon were real and Pokemon battles weren't forbidden but there were some rules.
1. Only one Pokemon are you allowed to have, not six.
2. You aren't allowed to battle if your Pokemon knows any TMs or Tutor moves. You are allowed to only teach it level-up and breeding moves.
3. No items given to them.
Which Pokemon would you choose, what moves would you give to it and how would you train it?
I would capture a Chansey and eventually evolve it into Blissey. I would train it for max defense, some HP and some Sp.Def - 212 HP/252 Def/46 Sp.Def
I would teach it Softboiled, Refresh, Egg Bomb, Counter(through breeding) or Softboiled, Sing, Egg Bomb, Counter.
I think I would opt for the second though. Sing can come in handy.
Blissey would be a very tough opponent. Humongous HP and sky high Sp.Def mean that only physical Pokemon would have a chance against her. To be more exact, only fighting Pokemon could beat my Blissey. Blissey is never OHKOed by any neutral physical attack due to her HP. So one Counter would be the end of the battle.
Also, Sing could be useful, Egg Bomb to deal damage :/ and Softboiled to heal herself.
The opposing Pokemon would probably just run out of energy and faint from exhaustion. Blissey could keep stalling it all the time with her endurance and Softboiled.