A BLJ, short for Backwards Long Jump, can be referenced as one of the Super Mario 64 speedrun tricks that SimpleFlips masters.
He has used it in numerous situations like: "The BLJ", "2 hours BLJ: The Sequel", "The Castle BLJ", "THE MEGA BLJ", etc.
In this technique, the Mighty Plumber long jumps in the opposite direction that he is facing and thus backwards long jumping. When he does it when the geometry is correct, he obtains insane amounts of speed.
In order to perform a BLJ, the Mighty Plumber must either be trapped under a solid surface or moving up a steep walkable slope.This has spawned many sub-jokes, such as IRL BLJ.