Suicune

Suicune is one of the best blanket check Pokemon in the GSC OU metagame, using its impressive defensive stats to check many threats such as non-Curse Snorlax, Nidoking, Marowak, Tyranitar, and Charizard. Suicune's lack of physical weaknesses makes it great against most physical attackers, and it also fares quite well against mixed attackers, as they are typically vulnerable to Toxic when dropping Rest for status moves or coverage attacks. It will sometimes draw comparisons to other Water-type Pokemon like Vaporeon and Starmie. However, while Vaporeon can also run a RestTalk set, its lack of physical bulk means it is a far inferior wall and should instead focus on setting up with Growth. Starmie is very effective and versatile with Rapid Spin, a resistance to Fighting, Recover, and even STAB Psychic for Gengar. STAB Thunder OHKOes it, however, and status greatly hinders it unless there is Heal Bell support. Also, since Suicune's combination of Surf and Toxic hinders almost every Pokemon in the metagame, it has a surprising offensive presence of its own for such a defensive Pokemon. However, the prevalence of RestTalk Zapdos and Raikou limits its offensive potential and often relegates it to a defensive role.