Chansey

Chansey's unbelievable bulk is metagame-defining, shaping the tier's special attackers around it and carrying the stall archetype on its back. Devastating threats like Ash-Greninja, Mega Alakazam, Volcarona, and Mega Charizard Y all fall under the same umbrella of being stumped by Chansey. It isn't especially vulnerable on the physical side, either; it has no issue with taking hits from Landorus-T and Diamond Storm Mega Diancie and can heal off Psyshock from Choice Scarf Tapu Lele. It can spread consistent damage with Seismic Toss and has the choice of either Toxic or ​Thunder Wave to further punish switch-ins. Additionally, it has support options like Stealth Rock and Aromatherapy, offering even more to teams it's put on. Chansey isn't invincible, though; it has no passive recovery, so it's vulnerable to being chipped down by pivot moves, entry hazards, and other forms of passive damage. Taunt users like Heatran and Tapu Fini can prevent its healing and ensure it stays too low to do its job properly. Lastly, wallbreakers like Mega Medicham, Mega Mawile, and Manaphy are able to crack Chansey open.