King K. Rool (SSBU)/Down special
King K. Rool puffs out his armored belly before bouncing attacks off. Gut Check serves as both a counter and a reflector, giving K. Rool a degree of flexibility in how he can use the move. This allows him to stave off pressure in disadvantage, especially during ledgetrap situations. Gut Check is tied with Mii Brawler's Counter Throw for second most powerful counter in the game damage-wise, at 1.5× damage, with the highest damage being Joker's Tetrakarn.
Gut Check's purpose allows it to function as a combo breaker or method of resetting neutral. With intangibility on frame 4, this makes it K. Rool's fastest combo breaker other than air dodge. Most players will watch where a combo is going to decide whether to Gut Check or airdodge, as it has incredible reward the counter on hit, at least in terms of damage. Gut Check has a minimum of 12% damage, and a maximum of 50%, which deals significant knockback. In addition, even when reflecting moves, the damage of the belly's counter hitbox will go up, enabling it to function as a multihit; however, the gust of wind's hitbox does not trigger in this scenario. As such, if reflecting a move like Charge Shot up close, it's possible to deal 100.4% in a single blow, which is almost guaranteed to be a one-hit KO. This is the only reflector capable of pulling this off.
Gut Check has an enormous hitbox when the counter goes off, making it very difficult to avoid if it's triggered. The searchbox for the counter goes below the stage, past the feet as of 6.0.0, making it consistent for sniping recoveries below the ledge, such as Chrom's Soaring Slash. In addition, the K. Rool player can have the counter turned around; this can be used to target other opponents in doubles by having a teammate trigger the counter, or hit an attacker's hurtbox extension through the counter. This can be done on reaction by the King K. Rool player, as it has a formidable amount of freeze frames before the counter activates.
Gut Check can also be used for survivability, by virtue of its 0.5× horizontal air speed multiplier and 0.0025× vertical air speed multiplier. While K. Rool will be KO'd around 5% earlier, with awareness of KO percentages, it is possible to aid in recovery through keeping both jump and air dodge as mixup options. It also takes K. Rool out of tumble, which allows for up aerial to be buffered without any risk of the upward drift not going off. This generally aids stalling recovery to exploit the additional ledge intangibility frames as well.
Unlike many counters, Gut Check has an unnatural amount of intangibility frames. This allows the move to dodge grabs and sometimes reflect moves from behind (such as Thunder Jolt, Boomerangs and similar attacks). However, in a grab scenario, opponents usually maintain the most frame advantage due to Gut Check's failure lag. Most K. Rool players buffer neutral attack or spot dodge in these scenarios in attempt to score a punish, thanks to their decent frame data. In addition, King K. Rool gains full-body invincibility after using Gut Check, absorbing hitboxes rather than simply passing through them, significantly reducing the chance of him being hit post-Gut Check. It's also a very quick counterattack with a lingering hitbox, being active frame 2-5 if not reversed. The invincibility is also longer on the reverse Gut Check, meaning this can technically be used to absorb more attacks should the player want to do that.
However, Gut Check has some significant downsides, the main one being its whole second of lag on use. While a successful attack is quick, the failure is not, lasting well over 40 frames. As a result, a failed Gut Check can potentially be a stock, allowing for charged smash attacks and other heavy-hitting attacks to be used against it. Gut Check doesn't cover K. Rool completely either; as a result, hitting K. Rool in the face is possible so long as the intangibility isn't active. Many projectiles can completely bypass Gut Check through this, making it one of the worst reflectors in the game for the intended purpose. Reversing Gut Check, while the payoff is immense, is very inconsistent even when reacting; this makes it difficult to determine risk/reward and potentially drops valuable damage and control of the game, despite the low endlag to the attack. The reward for a reverse Gut Check is also a bit low: despite the difficulty landing it, as well as the hit frame being 2 frames slower, the power remains the same. Furthermore, Gut Check has a noticeably weak sourspot on the gust of wind; while this deals the same damage, its KO power is noticeably low. On top of this, it has an angle of 45 unlike most (usually 361, which often works out to be 35), making it easier to DI than most counters.
Both variants of a successful Gut Check have the same knockback and damage statistics.