Edge running glitch
The edge running glitch is a glitch in Super Smash Bros. Brawl, Super Smash Bros. 4, and Super Smash Bros. Ultimate which allows a character to run against a platform's edge without falling off. It involves running towards an edge and holding the control stick in a particular fashion before arriving. While it can be done simply by relaxing the stick towards the neutral position, it is slightly easier to accomplish by rotating the stick into a diagonal position (without going far enough to input a jump or crouch), allowing a reduced sideways input while still holding the stick against the edge of its well. The glitch works because the "amount of tilt" required to move off an edge is higher than the "amount of tilt" necessary to maintain a run once it has begun. The more complicated a platform is, the harder it is to perform the edge running glitch, and as a result it's the hardest to do this glitch on slopes like Yoshi's Island.
The glitch has very few uses, as maintaining a running state means that the player cannot use the majority of their attacks, and it can be tricky to maintain for a period of time. Its only potential usage (aside from simple mindgames against opponents unaware of its existence) is in surprise usages of powerful dash attacks (such as King Dedede's) on opponents that are recovering overhead.
The glitch cannot be done if there is a ladder under the edge. The character will use the ladder instead.