Ness (SSB)/Down tilt
Ness's down tilt in Super Smash Bros. involves Ness doing a small very fast low kick which deals 3% damage and very low knockback. The move comes out on frame 4 and has an FAF of 14, making it one of the fastest tilts in the game. In addition to this, Ness can perform another down tilt on frame 11 (which will come out on frame 14, the same frame he would normally be able to perform another option). Down tilt has very short range, even compared to Ness' other attacks.
The main downside the move has is its extremely poor knockback. The move barely causes any hitstun, which makes the move negative on hit at realistic percents. The move is -7 on hit at 0% which allows almost every character to land an easy punish on Ness just by getting hit by the move. They can potentially grab Ness, use a combo starter and some characters can even land a powerful Smash attack if they have a fast enough Smash attack, simply by getting hit by down tilt. Performing a second down tilt does not help Ness much either as it comes it the same frame he would be able to shield. The move does not become neutral on hit until 150%-230% depending on the opponent's weight and as the move is -1 on shield, the opponent is always better off getting hit by the down tilt rather than shielding it. If the opponent does shield, a second down tilt will beat almost every out of shield option (besides, Quick Attack, Screw Attack and Spinning Kong) although as the move is more punishable on hit, the opponent is better off using an out of shield option to take the hit rather than letting Ness hit their shield again. Because of this, down tilt should rarely be used on stage as the reward for landing it is far too low, especially compared to Ness' other moves.
Down tilt is not entirely useless however. The move can be used to intercept characters with poor recoveries such as Fox, as the opponent has no safe way to punish Ness for landing the down tilt. The down tilt can then potentially set up a down aerial although some characters can easily avoid this and in most scenarios, Ness would be better off performing a double jump cancelled down aerial on its own.
Overall, down tilt is one of Ness' worst moves, as well as one of the worst down tilts in the game as its reward is far too low for its risk and Ness almost always has better options.
Earliest continuable is for another down tilt only.