King K. Rool (SSBU)/Down smash

Hitbox visualization showing King K. Rool's down smash.

Overview

A belly flop, emphasising K. Rool's huge weight and armor. King K. Rool's down smash is among his most notorious attacks, for its Belly Super Armor and hurtbox shift specifically making grabs miss. This is because K. Rool's hurtbox shifts above grab hitboxes as soon as frame 4. While it deals less knockback than forward smash, it remains a monumentally powerful attack, ending stocks as early as 80%. Due to this, K. Rool's down smash is largely considered to be one of the best down smashes in the game.

Down smash is one of the most difficult moves to challenge on startup in the game, due to the aforementioned hurtbox shift and Belly Super Armor. Low attacks and regular grabs simply miss, and regular or high reaching attacks tend to hit the armor. The only feasible way to challenge the move is to attack from above, where K. Rool completely lacks any armor.

Unlike many of K. Rool's attacks being designed to be difficult to challenge but with high endlag, down smash is reasonably well-defended even after the initial slam is over. It has a small quake hitbox just outside of the body slam's range, much like down tilt's. This quake gives sizable frame advantage on hit, but generally not enough for solid followups outside of forward tilt. However, if shielded, this quake hitbox doesn't have much shieldstun at all, leaving K. Rool dangerously open regardless; the quake is -34 on shield, enough for even charged smash attacks to be valid punishes.

Down smash typically isn't used outside of reads and hard punishes, however. This is because the move is quite slow, with Belly Super Armor not switching on until frame 11, and the hitbox coming out frame 22. It has an enormous FAF as well of 64, although this is the middle ground in terms of K. Rool's smash attack FAFs. On top of this, in situations where down smash can be done for free early stock (such as shield breaks or highly punishable moves are used), forward smash angled upwards would KO much earlier. In addition, if Belly Super Armor is damaged, K. Rool becomes very vulnerable. It has 14 active armor frames in total, which is enough for at least some heavy hitting attacks to hit it, especially considering how the move is used. As a result, many armor breaks occur from down smash misuse. As a result, in higher level play, down smash tends to be used far less on average.

Contrary to popular belief, while K. Rool leaves the ground as soon as Frame 4, he maintains a foot hurtbox extension until frame 7, which makes it deceptively easy to grab him up close. It is even possible - in fact easier - to grab K. Rool out of down smash when he has began the belly flop. This is commonly seen with tether grabs such as Samus', or large pivot grabs such as Greninja's. Command grabs such as, humorously, K. Rool's Blunderbuss Vacuum, can also force him out of it.

Hitboxes

ID	Part	Rehit rate	Damage	SD	Angle type	BK	KS	FKV	Radius	Bone	Offset			H×	SDI×	T%	Sound	Hit bits	Hit part
Early
0	0	0	18.0%	10.0	Standard	65	80	0	6.0	top	0.0	7.5	10.5 to -4.5	1.0×	1.0×	0%	Kick	All	All
Late
0	0	0	18.0%	10.0	Standard	65	80	0	6.0	top	0.0	5.0	10.5 to -4.5	1.0×	1.0×	0%	Kick	All	All
Quake
0	0	0	4.0%	0	Standard	80	30	0	11.0	top	0.0	9.0	23.5 to -13.5	1.0×	1.0×	0%	Kick	All	All