Wall cling

Wall clinging (known as AttachWall via internal files in Super Smash Bros. Ultimate) is a technique introduced in Super Smash Bros. Brawl. As the name suggests, it allows the player to cling on walls. The wall cling is performed similar to a wall jump, except the control stick or d-pad is held towards the wall instead of being moved in the opposing direction. Only certain characters have the ability to wall cling. While clinging to a wall, characters can jump, allowing it to function like a wall jump. This can be achieved by pressing away from the wall or by pressing up or the jump button. If the control stick is pressed away from the wall, the character will wall jump off the wall. If it is pressed up, the character will instead double jump. Wall clings will not restore a character's double jump. All characters with the ability to wall cling can also wall jump, and may do so from the wall cling. Steeply horizontal walls, such as the ones found on Battlefield, cannot be clung to.

Additional wall clings and subsequent jumps can be performed without having to land. If used correctly in combination of wall jumps, one can get a huge vertical distance if there is a wall, allowing characters that can wall cling have a huge chance to survive sudden death if used properly. Players can also utilizes wall clings to both throw off edgeguarding opponents and stalling in area they might have trouble reaching.

The time that the character can cling to the wall for decreases each time the they perform a wall cling without touching the ground. For the first two wall clings, the character can stick for up to 3 seconds, and on consecutive clings the time is divided in half.

Corrin and Sephiroth both have attacks that can be used as a pseudo-wall cling, Dragon Lunge and forward aerial respectively. While not being true wall clings, they can be used in similar ways and achieve similar results.

Wall clingers
(*)Additionally, if Lucario's Extreme Speed is aimed into a wall, Lucario will cling to the wall.

Origin
Various Smash characters have used wall clinging in their source games. In Kirby Super Star, when Kirby had the Ninja copy ability, he had the ability to wall cling. In other games, such as Super Mario Galaxy and Metroid Prime 2: Echoes, Mario and Samus could stick to walls temporarily if they were in the process of wall jumping; however, this would only last for a second or two before they slid downwards. In Super Mario Odyssey, Yoshi could wall cling after sticking his tongue at a wall surface. However, none of these four characters can wall cling in Smash.

Diddy Kong could situationally wall cling in Donkey Kong Country 2: Diddy's Kong Quest, as he could stick to honey-covered walls in and he has the same animation in Brawl for wall jumping from that game. He can also cling and crawl on grass-surface walls and ceilings in some of the levels in Donkey Kong Country Returns and Donkey Kong Country: Tropical Freeze, such as  and. Bayonetta's ability to wall cling is likely based on the Witch Walk ability from her home series, which allows Umbra Witches to walk on walls in moonlight.

Trivia

 * All characters who can wall cling can also crawl, except for Bayonetta.
 * In the Distant Planet stage, characters that wall cling on the top part of the Bulborb's mouth will get stuck inside its mouth and it will walk off the screen, causing a self-destruct.
 * Sheik is the only character introduced prior to Brawl who can wall cling.