Forretress

Forretress is one of two viable Pokemon in GSC Ubers that is able to set Spikes, with the other one being Cloyster. When compared to Cloyster, the benefits Forretress brings are primarily defensive in nature; being blessed with the Bug / Steel typing means it is immune to the status move Toxic and resists Normal-type attacks, so it can repeatedly afford to come in multiple times on the format's most centralizing threat, Snorlax, to set entry hazards and spin. This typing also gives it an excellent matchup against defensive Pokemon such as Celebi, taking minimal damage from its STAB moves and can use it as an opportunity to remove hazards or set them up. This defensive prowess comes at a large cost; Forretress is incredibly passive barring the few good matchups it has, and it is threatened by a myriad of Pokemon due to often having to use Spikes + Rapid Spin on the same moveset. Zapdos, Mewtwo, and Ho-Oh all threaten it, and even stray neutral hits from Pokemon like Skarmory and Tyranitar can rack up over time until it can no longer do its job. This means that it should not be used as aggressively as Cloyster, as every stray hit matters with Forretress, and careful positioning is required to ensure that Forretress can get the most use out of its function.