Belly Super Armor

Belly Super Armor (referred in the Techniques menu as Belly Power) is King K. Rool’s fighter ability. During attacks where his belly sticks out, his gold-plated stomach armor grants a special form of damage-based armor. This isn't to be confused with the armor on Crownerang, which is a wholly separate mechanic.

Overview
Belly Super Armor provides K. Rool with a unique form of launch resistance during specific attacks. Despite King K. Rool always wearing this piece of armor, Belly Super Armor is not active when idle; it has to be made active by his attacks. As such, it is never active unless he executes them, such as his forward tilt. While the Belly Super Armor is inactive, it will not take damage and K. Rool will be hit as normal, but it will still restore HP. Attacks that hit K. Rool's Belly Super Armor make a loud, distinct clanging sound as an audio cue, and the damage received is halved. If K. Rool's armor blocks an attack that triggers a Special Zoom, the attack will be blocked as normal, but the zoom still occurs.

Belly Super Armor has its own hurtbox, centered on his waist and jutting out slightly. As a result, this can be taken as a hurtbox extension. Due to this, K. Rool's armor can be attacked when K. Rool himself usually wouldn't be. This adds a degree of protection against longer-lasting hitboxes, but multihits, ranged hitboxes, projectiles are more effective at pressuring it due to this issue.

When an attack is blocked by Belly Super Armor, there is a minimum 16 frames of hitlag, during which the crack stages are updated. As a result, though, it is possible to buffer options, such as a fast fall, during this hitlag. K. Rool players will use this during neutral aerial against multihits, aiding in landing. If Belly Super Armor is broken, there is a universal 1.8x hitlag multiplier as well.

Belly Super Armor's strength and utility comes from the attacks that make the best use of it; each attack uses the armor in a different way. Neutral aerial allows K. Rool to "flash" the armor when needed, while being one of the most non-committal moves he has. With this, he can use Belly Super Armor to absorb a single-hit hitbox such as a projectile, gaining monumental frame advantage to punish the opponent. This can also start combos or defend K. Rool when recovering, making it a very powerful attack. Dash attack serves a similar purpose to Wonderwing, acting as an armored burst option to force his way through obstacle courses made by characters such as. However, while these attacks make K. Rool act more like a tank, moves such as up aerial serve more as defensive tools; in this case protecting him when trying to using the drift mechanics to recover. Down smash also serves as a defensive tool, hard punishing opponents for getting too comfy when pressuring him. Overall, Belly Super Armor serves multiple different purposes, and it all stems from the way his attacks utilize it.

However, while a monumentally powerful tool, Belly Super Armor isn't without flaws. If K. Rool's armor takes enough damage, it will break, and the camera will Special Zoom on him as he is flung into the air on the spot and will become temporarily dizzy, using shield break mechanics. If his armor is broken in midair, King K. Rool will slowly descend until he lands on a platform or stage base, while also being intangible thanks to shield break mechanics. These mechanics applying mean he can potentially be KO'd by having his armor break off-stage, or if he is pushed off during the descent. If the armor is broken and then K. Rool is hit, the armor will restore at full HP again, unlike shields which restore at half health.

As with shields and other forms of armor, Belly Super Armor cannot block unblockable attacks, grabs or hit-grabs, such as 's Buster Wolf. Furthermore, Belly Super Armor specifically protects K. Rool's stomach, which means hitting him in the face or from behind is a viable countermeasure. Some projectiles, such as 's forward aerial, are very well-suited to exploiting this weakness if aimed with precision. In addition, it is possible to simply muscle through the armor with multihit attacks, overriding the armor frames completely, and sometimes cancelling the attack entirely. However, this is a rare occurrence. Overall though, Belly Super Armor is a valuable aspect of King K. Rool's playstyle.

HP System
The armor has 18.01 HP (14.01 HP prior to 8.0.0), but since the incoming damage is split 50/50 between K. Rool and his belly, it is effectively 36.02 HP, often referred to by % by the K. Rool playerbase to differentiate. Belly Super Armor regenerates 0.08 HP every 16 frames, or around 0.3 HP per second. For an easier-to-scale format it takes 4 seconds to recover 1.12 HP. Overall, it will take around 60 seconds (47 prior to 8.0.0) to recover all of Belly Super Armor's HP. Due to the power of the ability, managing the armor's health is pivotal in being successful with King K. Rool.

Unlike other forms of armor that use damage for thresholds in Ultimate, Belly Super Armor is affected by the increased damage caused by the 1v1 multiplier, as unlike other attacks it must first calculate the incoming damage before it can split the damage (and thus requires the final post-multiplier damage). This is worsened by the stale-move negation mechanics strengthening fresh moves by 1.05×, with moves such as Warlock Punch specifically breaking the armor with the 1v1 and freshness multipliers considered. However, staling can also help the armor due to decreased damage thereafter, making it harder for characters reliant on a few specific attacks to break it. In addition, with the changes in 8.0.0, it is far rarer to see moves break the armor in a single hit.

Armor is also affected by other damage multipliers such as Monado Arts, Revenge and, making the armor deceptively easy to break for characters utilizing them. Due to the armor's active frames, it is also possible to destroy it through counters. However, as of 8.0.0, it is impossible for any counter to break armor in a single hit, including Vision affected by the Buster Art. Forward tilt and down smash are also impervious to this tactic due to their armor hurtbox terminating when the hitbox comes out.

Crack Stages
Unlike most forms of armor, Belly Super Armor reduces the damage K. Rool takes from attacks, cutting the damage in half. The amount of damage the armor has taken is roughly visible as a crack that expands in two stages. Small cracks appear when the armor has 11.5 HP left, and large cracks appear when it has 6.1 HP left. Thus, a K. Rool player can use this as a way to help manage the armor's HP during a match, prioritizing different moves accordingly based on the matchup. Shielding (sometimes also tilting the shield) is the most common method of checking the armor crack thanks to it visualizing the armor almost completely. Neutral aerial is also used as it expands the belly. However, this is risky as it also has the armor become active while making K. Rool commit.

Update History
 

Trivia

 * Oddly, Belly Super Armor will not regenerate health if the game speed is altered, either via Special Smash or Training Mode. The cause of this glitch is unknown.
 * The Techniques menu does not list King K. Rool's up air, down air, and side taunt as moves possessing Belly Super Armor. Interestingly it does list Gut Check which, as a counterattack, does not utilize armor at all.
 * Parameters reveal that using Gut Check was meant to have K. Rool take Belly Super Armor damage at some point during development, with a specific damage multiplier. However, this multiplier is 0, making it not occur at all. His scripts also request for damage to the Belly Super Armor, but they do not occur. It can be theorized that the clanging sound during Gut Check comes from this feature.
 * Contrary to popular belief, Crownerang does not use Belly Super Armor. Instead, it has standard damage-based armor against anything that does equal to or less than 12% damage (6% prior to 8.0.0). As the belly is not involved, King K. Rool receives the full amount of any damage that was armored as with normal damage-based armor.