After getting a life lesson from Bill and learning that there are
more than 150 known Pokémon species, the friends learn from Bill that
there is only one Pokémon he is searching for, which he claims is the
biggest Pokémon ever. He says it is unique and that no one had ever
laid eyes on it. One night, he says, he heard a strange noise coming
across the ocean from the Pokémon, but that was the last time he heard
it.
So this Pokemon is big
As Bill is reminiscing, the same sound is suddenly heard, and a large
figure appears, rising from the ocean. It is revealed to be the
outline of a Dragonite. As it comes closer to the lighthouse, Team
Rocket is shown scaling the cliff and, upon seeing the giant
Dragonite, they begin launching a barrage of missiles to try to catch
it. This angers Dragonite, and it smashes the top of the lighthouse
and begins to walk away. Bill calls out at it to stay, but to no
avail.
I hope this answers your question
http://bulbapedia.bulbagarden.net/wiki/EP013