Kingler is a crustaceanPokémon resembling a crab. Its strong shell covers the outside of its body, featuring a red upper half and a light tan lower half. Its upper half is topped with six tall, thin spikes that resemble a crown. Its light tan arms are also connected to its upper body. Its lower half doubles as its jaw with six fangs overlapping its upper body. Its two outer fangs are much larger than the inner four and are roughly half as tall as Kingler's entire body. Its hips visibly protrude from its lower body and connect to its four long, thin legs. Each leg has a single, claw-like foot. Kingler's main features are its orange pincers. Its left claw is roughly twice as large as the other and is as hard as steel.
Kingler is often found on the edges of water, usually the ocean. Its powerful claws have 10,000 horsepower and are capable of prying open the shells of Shellder and Cloyster. While Kingler's large, left claw is its main tool for offensive maneuvers, it is so large and heavy that Kingler can barely lift it. It causes balancing problems and Kingler may quickly become fatigued from continuous use. However, it has been shown to communicate with other Kingler by waving its pincers around. Prior to Generation III, Crabhammer was its signature move.
As Gigantamax Kingler, it has gained a larger, spikier appearance. Three red clouds float around the crown spikes on its head and the white sclera of its eyes are bright red. It now has foaming bubbles around its mouth in the shape of a mustache and long beard. The left pincer of Kingler has become much larger and its arms and legs have become longer as a result of Gigantamaxing. There is white, striped armor similar to teeth inside the pincers. The arms and legs both have several spikes. Kingler's claw-like feet have become orange and straighter.
The left pincer of Gigantamax Kingler can destroy anything it hits. The bubbles it releases are strongly alkaline. Should any opponent be struck by the bubbles, their bodies will quickly melt away.
In The Battle of the Badge, Giovanni used a Kingler during his Gym battle against Gary's Arcanine. Despite the type disadvantage, Kingler was defeated. He later loaned it to Jessie, James, and Meowth when he put them in charge of the Viridian Gym. Kingler managed to keep Ash's Bulbasaur at bay, but it was driven off by Pikachu. Another Kingler was seen being held in a cage.
Kingler appears to be very similar to a fiddler crab or a terrestrial crab of the genus Cardisoma, which usually have one claw larger than the other. Crabs from the Eriphioidea family also share this trait, with one of its members, Pseudocarcinus gigas; being one of the largest crab species in the world. It may also draw inspiration from pliers and hammers. Conceptually, its crown of spikes and its name may allude to the king crab.
Its Gigantamax form may be based on Japanese spider crabs with a bubble beard, which may be a reference to the fact that crabs blow bubbles to keep oxygen flowing to the gills when they are out of the water. It also resembles a bearded king.