Belly Super Armor
Belly Super Armor (referred by 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 super armor. Despite King K. Rool always wearing this piece of armor, Belly Super Armor is not active when idle or during attacks that do not involve King K. Rool expanding his stomach. As such, it is never active unless he executes certain attacks, 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. Attacks that hit K. Rool's Belly Super Armor make a loud, distinct clanging sound as an audio cue, with a fixed 16 frames of hitlag. 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.
If his armor takes enough damage, the camera will Special Zoom on King K. Rool as he is flung into the air on the spot and will become temporarily dizzy, similar to a shield break. If his armor is broken in midair, King K. Rool will slowly descend until he lands on a platform or stage base. This means he can potentially be KO'd by having his armor break off-stage or if he's pushed off during the descent, akin to a shield break. As with shields and other forms of armor, Belly Super Armor cannot block unblockable attacks or grabs.
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 he usually would not be. This adds a degree of protection against longer lasting hitboxes. However, multihits and short ranged hitboxes typically become better against it due to this.
Belly Super Armor's Crack Stages
Unlike most forms of armor, K. Rool's belly armor actually reduces the damage K. Rool takes from attacks, cutting the damage in half. To do this, it splits the damage between itself and K. Rool. However, as with shields, King K. Rool's Belly Super Armor can only withstand a certain amount of damage: the amount of damage it has taken is roughly visible as a crack in his belly. Small cracks appear when the armor has 11.5 HP left, and large cracks appearing when it has 6.1 HP left. Thus, a K. Rool player can use this as a way to manage the armor during a match.
The armor has 14.01 HP, but since the incoming damage is split 50/50 between K. Rool and his belly, it is effectively 28.02 HP. It regenerates 0.08 HP every frame, or 0.3 HP per second. The armor is not affected by the 1v1 multiplier, meaning that it can't withstand some moves in 1v1 matches, such as Falcon Punch, that it could otherwise. Oddly, it does not regenerate health in Training Mode. Although patch 2.0.1 fixed it, an unknown later patch caused the issue again.
List of attacks that have Belly Super Armor