Wall
Walls are structures found on several stages throughout the Super Smash Bros. series. Walls are impassible by traditional methods, and are a key component in the makeup of a hard platform. Walls can cancel the momentum of a character that has been sent flying, and depending on launching speed and angle, can send that character in the opposite direction at a fraction of the knockback. Since Super Smash Bros. Melee, characters are able to tech on walls to both cancel their knockback momentum and quickly revert to their neutral falling position to act with either an aerial attack or their recovery. Melee also introduced wall jumping, a technique available only to a few characters, which allows them to jump off of walls (with mostly offscreen walls and very short walls having walljumps disabled); even if a character has no natural wall jump, they can perform a wall tech to achieve a functionally equivalent result. A bonus is awarded for hitting, but not teching walls multiple times in a short time span during a match. Samus, Link, and Young Link are capable of using their grappling tools to grab onto walls, which aided their recoveries. Super Smash Bros. Brawl introduced wall clinging, which is available to even fewer characters and allowed them to attach themselves to walls without automatically jumping off. Teching, wall jumping, and wall clinging return in Super Smash Bros. 4 and Super Smash Bros. Ultimate.
All walls will stop projectile attacks and dashing characters; dashing and running characters will crash into walls and stop moving (indicated by a special animation), though they can walk indefinitely into a wall (for no practical effect). The walls on Shadow Moses Island and Mishima Dojo can be destroyed by attacks, and otherwise have the same properties as regular walls.