Quagsire is a light blue bipedal, amphibious Pokémon. Its head is broad and round, having little of a neck to distinguish it from the rest of Quagsire's body. Quagsire's mouth is wide and its eyes are mere dots, giving it a look of simplicity. Quagsire has a wavy purple coloration on its back and a dark blue "fin" there that extends to its tail. Quagsire's arms have three fingers, and its legs have three toes.
The "fin" running down a female Quagsire's back is smaller than that of a male.
Despite being a Water-type Pokémon, Quagsire's Ground element allows it to harmlessly shrug off Electric attacks. Quagsire appear to be oblivious to pain, allowing them to frequently bump their heads while swimming without any adverse effects. It also has the ability to go long periods of time without food, affording it the luxury of waiting for its prey to come to it.
Quagsire are quite carefree and relaxed, and so typically swim without paying much attention to their surroundings. Because of this, they tend to bump into boat hulls. Once a year, when the moon is full, wild Quagsire collect round objects like balls and swim to Blue Moon Falls, where they attempt to shoot the balls to the top of a waterfall with their Water Gun attacks to see who can launch their objects the highest, with the apparent target being the moon. The day after, the objects float downstream and are considered to be blessed with luck from the Quagsire.
Quagsire live in extremely clean bodies of freshwater and muddy swamps. The presence of Quagsire in water is usually an excellent indicator that the water is very safe for consumption.
Quagsire hunts for food by leaving its mouth wide open in water and waiting for its prey to blunder in unaware. Because Quagsire does not move, it does not get very hungry.
This Pokémon was unavailable prior to Generation I.