Anti planking
Anti planking is a technique in Super Smash Bros. Brawl to counter planking, a technique considered overly powerful by the competitive Brawl community.
If performed incorrectly, the player may self destruct.
Performing the technique
The technique was discovered by Logic and put on Youtube by VideoGameBootCamp. Anti planking is described simply by VGBootCamp as shielding the planker's aerial attack to go through shield stun. During this, the character then SDIs off the stage and hits the planking character while they're under their aerial's ending lag. The timing for performing anti planking varies on what characters are involved, though a Meta Knight planking has the tightest window of opportunity.
Anti planking methods
Performable on Meta Knight
Diddy Kong
After SDI'ing off the ledge, Diddy Kong can buffer a down aerial. An advantage of this is that Diddy Kong will not self destruct if the player can recover properly.
Falco
Falco can use a down air for a near guranteed kill. However, it cannot be buffered and is virtually impossible to recover from after using the move.
Mr. Game & Watch
Mr. Game & Watch can use a down air to either meteor smash or stage spike the opponent. If the planking character does not try to hit Mr. G&W when G&W uses his down air, then it may be difficult to recover, as it is a stall-then-fall.
Marth
Marth's down air can be used to perform anti-planking, and while it will likely kill, recovering after using it is near impossible due to the high ending lag.