Its body is capable of storing electricity. On camping trips, people are grateful to have one around.
– Pokémon Sun Pokédex
Charjabug, or Bugbus as I’d like to call it, is in the family of the early bug Pokemon in Alola. But unlike previous early bugs, it’s actually pretty good stat-wise (as a comparison, Charjabug is the middle stage evolution, but it has higher BST than Butterfree (400 vs 395)). I used one in Sun. It’s slow but has good Attack and Defense, plus it learns useful coverage moves.
I think Charjabug is supposed to be based on a battery, but I see it more as a bus than a battery. Its cry even sounds like a bus honking. Plus its eyes have that sheen that makes them look like bus windshield.