Inklings side special in Super Smash Bros. Ultimate is their trademark Roller, which covers the ground with ink. Nintendo decided that the ink should interact with the physics of other special moves, and… perhaps you should judge for yourself if these interactions were intentional:
It would appear that the ink decreases horizontal distance traveled while either decreasing or increasing vertical distance. This seems to be selectively applied, however, on a move-by-move basis. Moves with slides appear to increase their slide distance dramatically, such as Meta Knight’s teleport, while others might get stuck all-together, such as Jigglypuff’s roll.
Source: Beefy Smash Doods