OMG, Pikachu killed Ash!
Ok, here is what happened. Ash wanted to give his Pikachu a bath, but little did he know that Pikachu didn't want a bath. As a result, like dropping a hair dryer in a tub full of water, he got himself electrocuted the moment he put Pikachu in the tub. So as you can see, Pikachu killed Ash. This is why Pikachu can't have a trainer. She kills them off faster then she gets them.