Charizard

Blessed with being the only Pokemon in OU with two Mega Evolutions, Charizard has found both of them to be top-tier threats. The first forme, Mega Charizard X, is known to be one of the best Dragon Dancers in the entire tier; the combination of a base 130 Attack and essentially a 1.33x boost on both of its main STAB moves thanks to Tough Claws allows it to OHKO most foes at +1 with STAB Flare Blitz, meaning it can sweep almost effortlessly through teams, especially given how easy it is to set up with such a great defensive typing. Furthermore, Mega Charizard X can utilize its amazing typing, bulk, and movepool to be very unpredictable; it can run a variety of sets, including a defensive set that utilizes Will-O-Wisp and even a Double Dance set that contains both Swords Dance and Tailwind to bring the pain on both defensive and offensive teams, respectively. Given all these traits, Mega Charizard X is simply one of the best Pokemon in OU and offers a lot as a Mega Evolution.

The second forme, Mega Charizard Y, is the most powerful wallbreaker in OU. At first glance, Mega Charizard Y's amazing Fire STAB type and base 159 Special Attack make it appear to be a powerful wallbreaker in and of themselves. However, Mega Charizard Y's claim to fame is its ability, Drought, which boosts its STAB Fire Blast's power even further, allowing it to OHKO or severely dent a significant portion of the tier, and makes Solar Beam a 120-Base Power Grass attack that takes only one turn to use, nullifying Water-types as possible checks. With Focus Blast rounding out the coverage, most of the metagame is in huge danger to Mega Charizard Y bar a select few—these are mostly limited to opposing Dragon-types such as Latios, Latias, Dragonite, Mega Altaria, and bulky Mega Charizard X and dedicated special walls such as Chansey and Cresselia. All of the aforementioned Pokemon are very easy to take advantage of, however; with the use of stallbreakers and Pursuit trappers, it is easy enough to clear a path for Mega Charizard Y. Outside of these Pokemon, Mega Charizard Y simply will dent the opponent's team every time it comes in, provided it can hit.

However, Charizard's base 100 Speed for both formes is no more than good and leaves it outpaced in such a quick metagame, which is compounded by a quadruple Stealth Rock weakness that severely hinders it from executing its job effectively—it is very easy to take advantage of this with the use of priority moves or faster attackers that can finish it off at such low health. Mega Charizard Y is an extremely easy Pokemon to pressure; while it OHKOes an absurd number of Pokemon, it often can be outsped and KOed by faster Pokemon unless it switches out, which can ruin the momentum at times. Mega Charizard X, on the other hand, is worn down very quickly between Stealth Rock damage, Flare Blitz recoil, and general miscellaneous damage. This makes it harder to sweep and wallbreak to an extent. However, despite these flaws, Charizard is no less than a metagame-defining Pokemon and should be looked at as such.