Zapdos takes the form of a large bird with black and yellow plumage resembling lightning. Its tail feathers stick out in several directions, furthering this illusion. A large crest of feathers decorates its head, and distinctive black rings encircle its eyes. Its beak is also very long and thin. Zapdos is part of the Legendary Bird Trio, along with Articuno and Moltres. While Zapdos is the smallest and lightest of the legendary birds, it is still a fairly large Pokémon. Zapdos is a combination of the word zap and the Spanish word for two, dos. This is because Zapdos is the second of the legendary birds.
Storyline
Mt. Moon 2: Zapdos, along with Articuno and Moltres, can be seen chasing Ash and Gary in the cutscene prior to Mt. Moon 2. When Ash escapes to Cerulean City, Gary is left alone to fight the legendary birds.
Diglett's Cave: In the cutscene before Diglett's Cave, Gary is seen successfully escaping the trio by returning his Fearow, having his Alakazam use Gravity, then escaping by sending Fearow back out while the trio is falling.
Route 17: In this level, Zapdos is battled as a boss.
Route 19: Having beaten Zapdos, you are surprised to find him still ready to fight more. Joey tries to sacrifice himself but Gary ends up doing it instead; Zapdos attacks Gary but then Ash's Pikachu appears and blocks the attack. After a brief conversation, Gary allows Zapdos to carry him away.
Viridian City: Zapdos brings Gary to Mewthree in this level, where Mewthree says "Zapdos, you have delivered Gary as promised. You're free to go and tend your baby". Zapdos then nods and leaves.
Power Plant: You go to the Power Plant by walking back to the Rock Tunnel to search for Zapdos. If a team of level 100 unhacked Electric-type Pokémon are brought to the level, you may attempt to recruit Zapdos to your team.