DAY 20: CHARIZARD
Charizard is one of the most popular Pokemon ever since Gen 1. Being a fire-breathing dragon, it sure is one Pokemon that my 6-year-old self would certainly want. Despite this, however, Charizard wasn't really that great in battle, with every new generation introducing something to deal with it, especially Gen 4 with Stealth Rock. Until Gen 6 came along...
Come Gen 6, and Charizard gained two Mega Evolutions, allowing it to finally be a threat in battle. The first one, Mega Charizard X, is physically based, and I like how they changed its typing to Fire/Dragon. Set up a Dragon Dance, and you could feel all those memories of beating every single RBY player around you with your Charizard. Plus its design is amazing by Mega Evolution standards.
Mega Charizard Y, on the other hand, is more specially based, with Drought for even more power. Top that with Solar Beam, and even Water-types have no chance.
Charizard: Nostalgia Regained.