Charjabug communicating with Grubbin using sound waves
Charjabug is a small, cuboid Pokémon resembling an insect. Its body consists of three square segments. The last two sections have a thin, ring-like marking and a stubby brown leg on each side. Each eye is covered by a blue screen and are only visible when they glow. Two short, yellow spikes extend from the front square: one on each side of its rectangular mouth. The mouth itself is gray and has two jaws that close sideways, shaped like a lightning bolt when open.
Charjabug is often found half-buried in earth or leaves, munching on humus. In its body is an electric sac, which it uses to store electricity generated by digesting food. The electricity it stores could run a household for a whole day and can be shared with other Pokémon. As shown in the anime, it can send sound waves to communicate with nearby Grubbin.
Charjabug debuted in So Long, Sophocles!, where it was caught by Sophocles. Ash was looking for a farewell present for Sophocles, who he believed was moving away, and decided to go look for a Charjabug at Rotom's suggestion. With the help of Pikachu, Rockruff, and Litten, he was able to dig one up and trap it in a cage. Ash later let it out after showing up to Sophocles's farewell party, and allowed him to catch it. Sophocles did so after battling and defeating it with his Togedemaru. Charjabug evolved into Vikavolt during SM106.
Charjabug and its evolutionary relatives were designed by Hitoshi Ariga.
Charjabug appears to be based on a cocooned bug and a battery. It may also be based on the denkimushi, a caterpillar in Japan that, when touched, can give a sting that is said to feel like an electric shock. In addition, it bears a resemblance to subway cars, which are typically powered by electricity and reflect its habit of living underground. It may be also based on a two-pronged electrical plug.
Based on its cry, Charjabug may also be inspired by an accordion.
Charjabug may be a combination of charge (as in to charge a battery) or charger and bug.
Dendimushi may be a combination of 電池 denchi (battery) and 地虫 jimushi (grub).