Have you ever tried Shell Smash/Weak Armor Macargo? If it has a Focus sash to survive a physical hit, it becomes Turbo, the World's Fastest Snail. But that's not the fun part. Macargo can learn Guard Swap. So after creating a very fast pokemon that has a lot of negative modifiers in the defense area, Macargo can use Guard Swap to cripple the defense of the opponent.