is a psychic- and flying-type legendary Pokémon found on the Whirl Islands
It is a creature summoned by the power of the Elite Four to destroy the humans, but the efforts of Yellow stopped it. It was then captured by the Masked Man and used for his plans.
Lance intends to summon Lugia in order to exterminate humanity, but the summoning is brief and foiled by Yellow.
Lugia is found by Gold, Crystal, and Silver on the Whirl Islands. Unknown to them, it is under the Masked Man's control, and though they attempt to capture it, the Masked Man ultimately interferes and has Lugia escape.
The Masked Man uses Lugia, along with Ho-Oh, to raid the Indigo Plateau.
Lugia is eventually freed from control and flies off.