How did Ash's Pikachu knock out Onix with an electric type attack?

This makes no sense, so someone please explain.

Pleaselog inorregisterto add a comment.

Onix was doused with water using the sprinklers.Water conducts electricity. Water also weakens onix who is Ground/Rock.

The water negates the immunity, something that is absent from the game but kinda makes sense in real life logic.

Hope I helped :)

Oftentimes, Pokemon anime rules do not follow Pokemon game rules. Some examples:

So basically, these are things that the anime creators either a) overlooked, b) didn’t care about, or c) left them for people to find out. And remember: GAME FREAK LOGIC.

Source

This question is quite old. But seeing that it has no selected answer, I thought I’d help by giving a rational explanation even from the game’s point of view.

Pikachu’s electric attacks have no effect on any ground type Pokemon. However, there are certain attacks that change the type of the opposing Pokemon. This includes Soak - a move that changes the opponent’s type to the water type.

We can assume that Pikachu used the move soak in a variation when it set off the sprinkler system because of the fire. This also explains why it took only a few thundershocks to take out Onix, which has respectable special defence in the early game.

Hope I helped you gamers!

Ground types are immune to electric type attacks, whereas rock types are not. They’re only strong against electric types. Its not impossible to defeat a rock type with electric type moves.