Cape

Cape, known in Japan as Super Cloak (スーパーマント, Sūpāmanto), is 's side special move in Super Smash Flash 2. It replaced F.L.U.D.D. in v0.2b of the SSF2 Demo. If it connects, it switches the direction that the opponent is facing and dealing 8% to any opponent it hits, but dealing no knockback. It can also reflect projectiles if timed correctly, and can be used to increase Mario's horizontal recovery. Mario can also use it to gimp other characters recoveries such as the Fox Illusion. If you use Cape after dashing, Mario will slide a little bit. The move is based on the yellow cape in Super Mario World.

Cape Glide
The Cape Glide (also known as CG or aerial cape extension) is an advanced technique which Mario could also perform in Brawl. To perform this you have to dash off a ledge and perform Cape as Mario as about to go off of it. Mistiming it will have Mario only go off stop at ledge and be able to grab it or he will perform an aerial cape. This technique is useful for mind games, mobility and edge guarding. Mario can save his midair jump when using this and can use any aerial. When Mario performs this technique the effects of cape last throughout the glide.

Cape Dash
The Cape Dash or the reverse Cape Glide allows Mario to perform the Cape Glide on stage. To perform this act like you are about to perform the Cape Glide, but instead perform a turn around as you are about to run off the ledge. This will make Mario perform a Cape glide on-stage. This is good for setting up mind games against opponents.

Origin
Originating from Super Mario World, the Cape was a power-up obtained from the Cape Feather, which enabled both Mario and Luigi to spin and attack with it (although Mario did not hold the cape in his hand during the spin attack, as he does in the Super Smash Bros. games), as well as flying great distances after a running start and floating softly back to earth when falling. Mario did not "fly", rather, but "glide", but could do so more or less indefinitely by diving and pulling up in a certain rhythm, and while gliding he could slam into the ground to create an earthquake capable of damaging all enemies on the screen. This is, of course, not present in the Super Smash Bros. games.

Trivia

 * In demo v0.9a; Mario will go into a landing animation after he performs cape on the ground. This is due to the move being coded jank to make the advanced technique Cape glide possible.
 * He is able to perform the Cape glide in v0.9b.