The Gappas (ガッパ, Gappa?) are a species of ancient birds. Two adult Gappas, male (ガッパ雄, Gappa Osu?) and female (ガッパ雌, Gappa Mesu?) and their juvenile son appear in the 1967Nikkatsukaiju film, Gappa.
In ancient times, the Gappas would fight other monsters for survival.
All three of the Gappas share common characteristics, being based on various reptiles and birds, such as eagles and hawks. The second parent lacks a head crest, and has a flatter face compared to their counterpart.
An expedition to Obelisk Island by Mr. Funazu uncovers a baby monster, who hatches from an egg near a sacred temple. The natives plead with the skeptical scientists not to take the baby away, lest it anger the baby's parents. Sure enough, they take the baby away, and soon, inside the caverns, its two parents rise from the underground waters beneath the volcano, destroying everything in their path. Saki, the only survivor, is rescued by an American navy fleet and brought back to Japan.
The parents storm across Japan, destroying all in their wake, but their assault ceases once they recover their child. Mercifully, they relent, and depart to return to Obelisk Island.
Gappa is one of the end results of Tsuburaya Productions' plans for their second Tokusatsu Series, which would ultimately become Ultraman. Originally, Tsuburaya had created a concept for a series called Scientific Special Search Party: Bemular, featuring a heroic bird-like monster followed by the SSSP. This concept was later modified heavily, with the original concept for Bemular being partly sold off to Nikkatsu, and adapted to become Gappa.
Part of this original design can also be seen in the bird kaiju, Hydra.