I'm going to have to agree with the people that said winning the arceus battle. I had to lower it's speed 3 times with mudshot from my swampert. Best part was that leftovers would restore most of the damage BUT arceus would use recover to restore the tiny bit of health he was missing. That final brick break felt wonderful. El didn't even get to use his full heals.
"Execute" No matter who the top dog of meteor is that, guy is still cold blooded.