Celebi

Celebi is one of the better utility Pokemon in the DPP OU metagame. Celebi’s access to reliable recovery, wide range of support moves, and Grass / Psychic typing gives it a unique list of Pokemon it counters. It is notably the best counter in the game to Breloom due to Natural Cure, resistances, and huge bulk and checks most offensive Water-types such as Dragon Dance Gyarados lacking Bounce, Swampert, Empoleon, and Suicune. These openings allow Celebi to take advantage of its wide support movepool with choices such as Thunder Wave, Stealth Rock, Heal Bell, U-Turn, and Perish Song. Celebi also can go on the offensive with boosting moves such as Nasty Plot and Calm Mind, allowing it to set up and take on defensive threats such as Clefable, Jirachi, Heatran, and Skarmory that invalidate defensive Celebi. Celebi also is unique in that nothing in the tier shuts down builds that don't have the tools to deal with it like it does—hyper offensive teams can really struggle against Celebi spreading paralysis and walling everything due to its huge bulk, while some slower defensive teams give Nasty Plot Celebi openings to break down the team with boosted attacks.

Celebi, however, is reduced to being niche in DPP OU due to the severe flaws from its typing and competition from Latias. Celebi is grounded and has seven weaknesses—of these, the five of Bug, Dark, Fire, Ice, and Ghost are the most critical. Celebi is 4x weak to U-Turn, meaning Flygon, Jirachi, Infernape, Zapdos, and Scizor can come in and freely gain momentum on Celebi, as even physically bulky Celebi is at least 2HKOed by most U-turn. Celebi's Psychic-typing means it is vulnerable to Pursuit Tyranitar, as it can’t OHKO Tyranitar without a boost. Celebi's other weaknesses open it up to Heatran, boosting Water-types with Ice-type coverage such as Empoleon and Gyarados, Rotom-A, and Gengar. Defensive Celebi also struggles broadly against bulkier teams, as it cannot hurt Clefable and its weak coverage options are otherwise easy to wall. Celebi struggles mightily with entry hazards, especially Toxic Spikes, but Spikes also neuter its great bulk. Celebi often cannot prevent Skarmory from setting up Spikes, either. Offensive Celebi is both easy to wear down and easy to force out, as it is forced to use Leaf Storm for power due to Clefable, Rotom-A, and other defensive Pokemon not being hit hard by Grass Knot or Energy Ball. Offensive Celebi gives up a lot of its defensive utility, as it relies on its Speed and power to check offensive Water-types and Breloom rather than numerical bulk. Celebi additionally struggles to differentiate itself from Latias, as Latias is immune to Spikes and Toxic Spikes, has much greater offensive prowess, and does not have as many weaknesses as Celebi does while having a similar set of resistances.