If you're interested in that strategy, Skarmory's the master of it with Whirlwind! Roar and Circle Throw also do this, although I've never seen Circle Throw used competitively. I've been meaning to try using Skarmory for a while.
Yep, it says so at the beginning of Showdown battles. And the accuracy is kind of a red herring. You don't even need a gimmick, because you could just have a really bulky Pokemon doing it. For instance, Guillotine Gliscor would probably be a nightmare. Also, even if you did need a gimmick, then Pokemon that were able to use that gimmick could become over-centralized, because a 1/3 chance is actually really, really high. You only have six Pokemon on your team, and your opponent only has to score a OHKO once to put a serious dent in it. Additionally, strategies that are that luck-based are kind of frowned upon in competitive battling -- things like evasion increasing moves and abilities are also banned.
Oh, well, that's okay. If you destroyed it, it should be easier to redo properly. But I thought the bot worked fine and it was just the Personality plugin that you couldn't get working? If that's the case, that was a version of Personality from before I updated it. It's much easier to set up now. I could try to help sometime if you wanted! There aren't too many supybot guides online.
JavaScript is okay! Have you looked at the Khan Academy JavaScript section? They put a lot of effort into keeping things simple. Also, the girl who talks for the JavaScript exercises talks about Pokemon. I've done some of the lessons there with my sister! She likes messing up all of the pictures.
Oh about 80% accuracy on Hydro Pump, did you know Veekun apparently has a feature that calculates the power based on the accuracy? It says "80% ≈ 88.0 power" on Hydro Pump. That's kind of interesting.
I thought it might be a mistake! But it seemed rude to say so if it really wasn't. And yeah, it was illegal before because it wasn't possible to breed a Marill that way! Since there were no Pokemon who could be fathers to Marills who knew both moves. But now that Pokemon can also get egg moves from the mother, you can do it.
Also, yay, you made the thread!
EDIT: Here's this regarding One-Hit-KO moves:
I vote yes purely on principle. Pokemon is hardly a balanced game in and of itself. As a competitive community, we have taken it upon ourselves to build up a set of rules that minimize the game's inherent imbalances and try and turn it into a fair competition, minimizing the factors that take away from pure skill. OHKO moves are one of those factors. They are an element of random chance that can determine the outcome of a battle at the mercy of the RNG, and this is something to be avoided.
Playing with OHKO moves is not the same as the choice of Hydro Pump or Surf, despite how it appears on the surface. Hydro Pump is a gamble to use over Surf, thanks to shaky accuracy. To choose Hydro Pump over Surf means that the user is taking the risk of no payoff for the chance of a larger one. Arguments in favor of OHKO moves claim that it is the same with these moves, just on a larger scale. However, the difference between OHKOs and other high power moves is that even the most powerful moves can be played around. If I predict Ice Beam or Blizzard, I can switch in Vaporeon or Milotic, and I have checked the attack. However, you can't play around OHKOs. You cannot check them with anything but very specific counters, especially Sheer Cold, where there is no type immunity. Unless you switch in these specific counters, you are at risk of losing something no matter what you did. Where is the skill here? If I switch in that Milotic expecting Ice Beam to get reamed by Sheer Cold, did I do something wrong? What could I have possibly done to prevent this? Anything that removes skill from the hands of a player such as this does not belong in a competitive environment.
I believe that we need to firmly realize that we are not a pure Pokemon simulator. We are attempting to play the game at it's most competitive, despite the random elements involved. While we cannot control the mechanics of the game, we can alter what elements we allow into it. Whether they would see widespread use or not, anything that directly removes the influence of skill from the hands of the players does not belong in the environment we are attempting to maintain. So, despite their impracticality, OHKO moves should stay banned for the sake of our principles.