Edge Cape-Cancel is a technique that can be used by Mario in Super Smash Bros. Brawl. It was noticed by many Mario players. It involves using Mario's Cape while hanging on the ledge. This allows the player to regain the invicibility frames aquired by grabbing the ledge, increasing the amount of time the player can be hanging.
How to perform
Simply grab the legde of the stage and, as soon as the invicibility frames are gone, press the Left Control Stick in the opposite direction you are facing and B. Mario will release the edge and perform his cape. When the attack frames finish, Mario will automatically re-grab the legde and gain more invincibility frames. This can be useful for Edge-guarding since you can hit opponents that are trying to recover with the cape and edge-hog afterwards.
Note that if you press the B button slightly before you smash the Control Stick, Mario will return to the stage instead of performing the Edge Cape-Cancel.