Electrode

Electrode (Japanese: マルマイン Marumain) is an -type Ball Pokémon introduced in Generation I. It is known to drift on winds if it is bloated to bursting with stored electricity. It's nicked named the Exploding Pokémon. Like Voltorb, Electrode is very easily mistaken for a Poké Ball. It can easily explode when hit or touched.

Evolution
Electrode is the evolved form of Voltorb, as of level 30.

Trivia

 * Electrode and Voltorb are similar to a battery. One side could be positive and the other negative.
 * When it evolves, it could flip and it's face will move
 * Electrode and Voltorb are mistaken as the Pocket Monster's mascot due to it having a similar appearance to the Poké Ball.
 * In HeartGold and SoulSilver, if the player has Electrode traveling alongside them, if they talk to it inside the Rocket Hideout one may receive a message say "Electrode is trembling" possibly indicating it is either scared or agitated being there likely due to Team Rocket's using Electrode to power their machine. As for the Electrode that can be captured inside the Rocket Hideout, it is possible they are remembering the treatment it endured while enslaved by Team Rocket.