Kirby (SSBU)/Down smash
A spinning split kick. It has the fastest startup of Kirby's smash attacks (frame 7), but the highest amount of ending lag (FAF 51, 31 frames of ending lag). It is a semi-spike, with Kirby's feet being intangible, starting from frame 3 and lasting until the clean hit ceases at frame 11. The clean hit deals 14% and has above average power for a semi-spike, while the late hit deals 10%. Due to its long active duration, it's Kirby's best option for 2-framing. The first hit forward aerial can also set up into down smash, although forward smash is generally preferred due to the latter’s higher knockback and more favorable angling.
As of patch 8.0.0, due to the changes of Kirby’s second and third hits of forward aerial, it can act as a consistent whiff punish kill confirm. Down smash’s higher knockback and faster frame data gives it more potency as a punish option, ledgetrapping option, and kill move.