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
Diddy Kong
After SDI'ing off the ledge, Diddy Kong can buffer a down aerial to hit even Meta Knight. An advantage of this is that Diddy Kong will not self destruct if the player can recover properly.
Mr. Game & Watch
Mr. Game & Watch can use a down air to also hit Meta Knight. 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.