Moves
Shift Gear fixes Regigigas's average Speed by increasing it to the point where it outpaces the entire unboosted metagame and increases its Attack stat, letting it OHKO most neutral offensive foes with Facade after Stealth Rock damage. Facade is Regigigas's primary STAB move that becomes immensely powerful after Regigigas has successfully activated its Toxic Orb. It also notably leaves Imposter users with only a 70-Base Power STAB attack due to them not being able to independently poison themselves. The third moveslot is filled with a sleep-inducing move, as it helps Regigigas bypass Focus Sash holders with some chance, defeat Imposter users, eliminate defensive foes that can handle Facade, and provide an extra turn of passive recovery. Spore is a reliable option because it cannot miss, and it synergizes well with Knock Off, as the attack can remove Safety Goggles. Lovely Kiss is an alternative option to be used when Regigigas does not opt for Knock Off that enables Regigigas to put Grass-type foes to sleep, prevents Kartana from easily revenge killing it, and reduces Ferrothorn's efficiency as a check. Knock Off rounds off Regigigas's coverage by allowing it to hit Ghost-types like Giratina and Aegislash super effectively while also being useful in removing items like Safety Goggles and Eviolite and in scouting for potential Z-Crystals. The removal of Safety Goggles is especially appreciated, as this lets Regigigas use Spore more freely. Spectral Thief, on the other hand, consistently hits Ghost-types hard and lets Regigigas shut down a boosted foe if it can survive a hit and hit back, and it is best used with Lovely Kiss or teammates with Knock Off so that Regigigas can set up on foes with Safety Goggles. It also notably improves Regigigas's matchup against other setup sweepers like Poison Heal variants of Primal Kyogre and Mega Tyranitar. On the other hand, Avalanche can be used to prevent Core Enforcer from suppressing Poison Heal and hit Giratina and Zygarde-C super effectively.
Set Details
Toxic Orb poisons Regigigas at the end of the turn, letting it utilize Poison Heal to gain passive recovery each turn, gain a pseudo-immunity to malicious status ailments, and use an empowered Facade to defeat Imposter users. A Jolly nature allows Regigigas to outspeed as many foes as possible, including base 90 Speed Pokemon like Primal Groudon, Primal Kyogre, and Dialga. An Adamant nature is an alternative option to improve Regigigas's damage output.
Usage Tips
Although Regigigas is able to switch into weak attacks from passive walls such as Registeel and Mega Audino, it should enter the field with caution before it has successfully activated Toxic Orb, as being afflicted by other status or getting hit by Knock Off significantly hampers its usefulness. Moves that Regigigas can switch into include predicted uses of recovery moves, weak attacks, and Spectral Thief. In this regard, it should only be switched in by slow pivoting moves or when the opponent is sure to switch their Pokemon out. However, Regigigas can be used more liberally to absorb status once it has been poisoned. Do not underestimate Regigigas's bulk; while it lacks resistances, it only has a sole weakness to Fighting-type attacks. Regigigas may sustain damage while setting up, but it will regain its health with Poison Heal recovery, which comes into play often with Regigigas's ability to induce sleep and force switches. This means foes such as Mega Mewtwo Y after using Psycho Boost and other offensive foes that cannot inflict serious damage to Regigigas are setup fodder. Once Regigigas has safely activated Toxic Orb, it can proceed to set up Shift Gear to threaten the opposing team or hinder walls with Knock Off should a foe with Safety Goggles switch in. Should Regigigas be facing more defensive teams, it is more beneficial to analyze how an opponent reacts to Regigigas. In this regard, using Knock Off early-game to remove items is a sensible strategy, as this will aid Regigigas's attempts to break past or take away momentum from Fur Coat users or most non-Magic Bounce foes later on. When setting up with Regigigas, scout for possible Core Enforcer and Entrainment users, as they can suppress Poison Heal and thus easily force out Regigigas. When Regigigas finds itself unable to set up against well-prepared teams, it can still support its team by putting foes to sleep or by double switching out to a teammate after luring in Magic Bounce users. When Regigigas is low on health, slow pivoting provides it with passive recovery, so take advantage of this when one is able to secure momentum. A few turns of Poison Heal recovery will bring Regigigas back to a healthy enough state so that it can take on defensive foes again. Once its checks and counters have been sufficiently weakened or eliminated, Regigigas can liberally switch into a passive foe, set up and proceed to overpower the opposing team with its overwhelmingly powerful Facade. Avalanche should be used against potential Core Enforcer users like Giratina to prevent the move from suppressing Poison Heal. Lastly, in an instance where Regigigas opted for Spectral Thief, it can offensively check setup sweepers that fail to OHKO Regigigas by stealing their boosts.
Team Options
Regigigas is hopelessly shut down by Giratina, so its best partners are Pixilate and Refrigerate users. Mega Diancie, Kyurem-B, and Kyurem-W can fit alongsides Regigigas in this regard, as they appreciate Regigigas overwhelming Steel-types by putting them to sleep or by removing important items like Assault Vest with Knock Off. -ate Pokemon also tend to pressure Magic Bounce users a lot, meaning they can take advantage of forced switches by setting entry hazards or pivoting out to Regigigas for a safe activation of Toxic Orb. Entry hazard support is generally appreciated, as Regigigas tends to force many switches and can't fit a move that is dedicated to defeating Sturdy Shedinja. Fairy-types like Mega Diancie, Xerneas, and Mega Audino can switch into Core Enforcer, as both Mega Diancie and Xerneas offensively force out Giratina, while Mega Audino can take momentum away from it. As a result, the presence of these Fairy-types can somewhat improve Regigigas's matchup against Giratina by making it more wary about using Core Enforcer in an attempt to check Regigigas. Stealth Rock also helps Regigigas meet important benchmarks, letting it OHKO Mega Blaziken and Mega Mewtwo X with +1 Facade after Stealth Rock, both of which would otherwise offensively check Regigigas. Strong Knock Off users such as Mega Gyarados and Mega Tyranitar can help Regigigas generate setup opportunities should it lack the move itself and pressure Ghost-types like Giratina and Aegislash. The mentioned Dark-type teammates can run more offensive sets with Choice Band to heavily weaken or eliminate Giratina. Regigigas, while it is bulky, tends to be vulnerable to being revenge killed by -ate users when weakened and is easily dented by strong neutral attacks from faster attackers. Steel-types can guard Regigigas from -ate users until they have been sufficiently weakened or until Regigigas is given an opportunity to set up and outspeed them. RegenVest walls can handle faster threats such as Mega Mewtwo Y and -ate users depending on their typing while letting Regigigas utilize the momentum they secure via slow pivoting.