Level 100 Statistics (see level 5, 50, 100)
Gorebyss's access to Shell Smash makes it a very dangerous setup sweeper that can do well against offensive and defensive teams alike. However, while it is powerful, it faces competition from another Shell Smash user, Carracosta, which has a priority move and can set up relatively easily due to its decent bulk and typing. Gorebyss, on the other hand, has trouble finding setup opportunities, especially against offensive teams, because most powerful neutral attacks do a lot of damage to it. Gorebyss also suffers from a slight case of four-moveslot syndrome; while its coverage is decent, it cannot cover every defensive threat at the same time. Gorebyss's low Speed leaves it extremely vulnerable to revenge killing even after a boost because almost every common Choice Scarf user can outspeed and OHKO it, even at +2. Even after Choice Scarf users are removed, Gorebyss still has to watch out for priority users, which can take it out easily after its defenses are lowered by Shell Smash. The large amount of team support required for it to sweep is something that needs to be considered when building around Gorebyss.
Shell Smash allows Gorebyss to become a fearsome sweeper and to clean up easily once opposing revenge killers are defeated. Surf provides a powerful yet reliable option for sweeping through the opponent's team. Signal Beam hits Grass-types such as Ludicolo and Exeggutor, as well as Jynx, which otherwise walls Gorebyss. For the last moveslot, Substitute is generally preferred, as it allows Gorebyss to set up in front of walls such as Torkoal, Alomomola, and Metang by shielding it from status. Substitute is also very helpful when the opponent's revenge killer is still alive in order to protect Gorebyss from opposing priority and Choice Scarf users. Ice Beam is an alternative, and while it does not provide insurance against revenge killers, it does allow Gorebyss to take down Roselia, Altaria, and Vileplume if its teammates are unable to do so. However if you go this route, be sure to defeat opposing Choice Scarf users first before attempting a sweep.
Team Options & Additional Comments >>>
Gorebyss has access to Baton Pass along with many potential boosting moves to pass to teammates, including Amnesia, Iron Defense, Agility, and Aqua Ring, making it a great option on full Baton Pass teams. However, do note that the combination of Shell Smash and Baton Pass is banned in NU. Toxic can be used to catch special walls by surprise and wear them down, but it is hard to fit onto Gorebyss's moveset, and Gorebyss is generally better off using attacking moves. Hydration, Rain Dance, and Rest could be used, but this is a waste of Gorebyss's potential, especially as its defenses are decent at best. Gorebyss could make use of Rain Dance and Shell Smash for a powerful and fast sweep, but it would be more efficient if its teammates were to set up rain for it, and boosting with Shell Smash twice is still more beneficial. Finally, Hidden Power Electric could be run in the last slot to destroy unsuspecting Mantine, but this option is rather situational.
Checks and Counters
Mantine is the ultimate counter, as it does not mind any of Gorebyss's common moves, can wear Gorebyss down with Air Slash, and constantly heals itself with Rest. Regice and Lickilicky are bulky enough to tank any one hit and retaliate with Thunderbolt or Body Slam, respectively. Specially defensive Ludicolo and Roselia can switch into Surf and hit back with Giga Drain, but they risk getting OHKOed with the appropriate coverage move with entry hazard support. Choice Scarf users, such as Rotom-A, Jynx, and Primeape, can easily revenge kill Gorebyss, even at +2 Speed. Kangaskhan can utilize two forms of priority moves in Fake Out and Sucker Punch to do the same. However, be mindful that all these revenge killing attempts are stopped cold if Gorebyss has an intact Substitute. Kangaskhan can also be beaten if Gorebyss sets up a Substitute against a Sucker Punch. The best way to defeat Gorebyss is to keep hammering at it before it sets up because this will either severely dent it or prevent it from successfully setting up a Substitute, which makes revenge killing much easier. Variants without Lum Berry also dislike Toxic Spikes, which shortens its sweep, so Roselia and Scolipede are great Pokemon to have when facing it, as they can set up Toxic Spikes and at the same time discourage Gorebyss from switching in and setting up due to their ability to OHKO it.