So, to let you all know something useful, anything that can reach 162 Speed will out speed everything, except maybe Ninjask
after a buhjillion Speed Boosts, or the seldom seen Tailwind, after one Speed Boost (or Choice Scarf). So, because of that, Mismagius makes a great revenge kill.
Memento is used in synergy with the Latios
Sweep (below) to make sure Latios gets a good Sub up, and Dragon Dances as much as possible. However, STAB Shadow Ball makes Mismagius a good revenge killing sweeper itself. Energy Ball gets a lot of SE, notably Lanturn
, which walls Starmie pretty hard. Power Gem would be helpful for coverage, but WoW helps when Latios is setting up (as it Stalls with Sub/DD until the opponent burns to death).