Dizzy Dealer Achievement
Stun online opponents 25 or more times
Go to online games and either choose matchmaking to group up with a random, or invite a friend to a private online match. Whatever you choose, during your games, jump over your opponent and hit and then to do a butt slam on them, stunning for a second or two. Do this 24 more times to unlock the achievement.
This can also be unlocked in an online match with two controllers, bouncing off your team mate's head (the second controller) 25 times.