Electrode is a Pokémon that appears out of a Poké Ball.
When Electrode comes out of the Poké Ball, it will just sit on the stage. Electrode will then start to get darker. This means that Electrode is about to explode. When it explodes, everyone in the blast radius (including the character who summoned Electrode) will take a good amount of damage, and it may even KO characters at a low percentage.
Electrode is different from the other Pokémon. Electrode can be used as an item also. When Electrode is about to explode and turns black, you can pick it up with the Z button. You have to be fast when picking it up though. If Electrode explodes while you are trying to pick it up, then your character will take damage also.