The Big One is the first boss of Frogger: Ancient Shadow and the boss of Tears Of Spirits. It is virtually a giant, aquamarine-colored salamander that Lumpy aimed to catch. It can shoot powerful jets of water that spread to other tiles on impact.
To defeat it, Frogger must ground-pound a 2x2 tile image on the floor, this will make a net fall on its head and make one of the three orbs on the right of the screen disappear (this is the boss's health meter). Frogger must be careful of his footing because when a jet of water is fired, it spreads to multiple other tiles on contact and linger for a while. He must also take care not to accidentally fall into the water (which he can).
After the fight, Lumpy comes and finds Frogger at his fishing spot. When Lumpy is determined to catch "The Big One" and "have a big fillet tonight", Frogger confesses "that he.caught The Big One". Frogger then tells Lumpy that weird things have been happening lately around Firefly Swamp, and that he intends to sort things out.
Having heard that Frogger defeated the intended catch, Lumpy is inspired and determined to find a "Bigger One" and have that for dinner. He even goes as far as to make friends with some Mini Wanis for help in order to accomplish this.
This is the only boss in the game to have only three health, and thus also has the lowest amount of health of any boss in the game. The following boss has four health, and every boss after that has five health.