Charizard

Fire

Blessed with an amazing ability in Drought and an incredibly high Special Attack stat, Mega Charizard Y is one of the best wallbreakers in the metagame. Drought boosts its Fire-type moves while weakening Water-type moves, removing other weather effects such as rain and sand, and making Solar Beam a one-turn move. To complement this, Mega Charizard Y has been gifted fantastic coverage through which it can OHKO or at least 2HKO almost everything in the metagame. It can also clear away entry hazards through Defog to help its teammates. Additionally, its pretty decent Special Defense stat lets it survive most special attacks in sun. To take further advantage of this, Mega Charizard Y can run Roost to improve its longevity. It notably is blessed with an immunity to Ground-type moves thanks to its secondary typing, Flying. Although its base 100 Speed isn't bad, the metagame is crowded with base 100 Speed Pokemon, which leaves it Speed tying with Victini, which can KO it with Bolt Strike, and Manaphy, which can set up Rain Dance on an incoming Solar Beam. It also has a relatively low Defense stat and therefore does not like taking physical hits. As it is a Fire-type Pokemon, it is weak to Stealth Rock as is, but its secondary typing makes it even weaker to it, leaving it with only half of its health if it comes in on it. Besides this, Mega Charizard Y can easily be worn down through priority attacks and other forms of residual damage. Although it is mostly used as a wallbreaker, its wallbreaking capabilities are heavily reliant on sun being up.

Flying

Mega Charizard Y's great Fire typing and base 159 Special Attack make it a powerful wallbreaker. Its ability, Drought, raises the damage output of its Fire-type STAB moves and makes Solar Beam a one-turn move. It also halves the damage of Water-type moves, which helps against Mega Charizard Y's Water-type matchup, as well as allowing it to viably use Solar Beam as coverage for Pokemon such as Seismitoad, Slowbro, and Swampert. However, despite Mega Charizard Y's decent Speed tier, it's generally frail and doesn't have the best Defense and HP. It is also checked by Dragon-types such as Garchomp, Dragonite, and Latias. Finally, due to its typing, it is 4x weak to Stealth Rock, so a Defogger is always needed.