Dedenne is a bipedal, orange, rodent-like Pokémon with a round body. It features round black ears with pale yellow interiors, black eyes, a tiny nose, and a prominent upper incisor with a slight point. Each cheek has a circular, dark orange electric sac adorned with two black whiskers. The upper whiskers are branched and resemble antennae, while the lower whiskers are simple. A thick black stripe runs down its back, and it has a pale yellow belly. Its limbs are stubby, each paw having three digits, and it has a long, thin black tail tipped with a tuft of fur.
The upper whiskers function as antennae capable of sending and receiving electrical waves. This ability allows Dedenne to communicate with others of its kind over great distances, sharing information about food or electricity sources and sensing its environment. The simple, lower whiskers are organs that can emit electricity. However, due to its small size, Dedenne's electricity-generating organ is underdeveloped, preventing it from generating much electricity on its own. Instead, it absorbs electricity from other Electric-type Pokémon or from human homes and buildings by plugging its tail into outlets. Because of this behavior, Dedenne often lives near humans. When its energy is low, it curls up and sleeps.
