This was the stunning effect of the lightning pillar. From above, on top of Thunder's back, Samuel could see that the rat seemed to be in great pain. This was to be expected as the lightning pillar was formed from lightning.
In just a few moments, the aura of the rat had reduced by half. And by the time that the lightning pillar disappeared, the rat was left with a lot of charred wounds on the surface of its skin.
Some of the injuries that had been caused by the lightning had even managed to penetrate deep into the body of the rat. That was mainly due to the fact that the rat did not have high defensive abilities.
Samuel nodded as he observed the situation. He did not expect that the finishing move that Thunder had would be able to easily deal with a monster that was a single stage above it, at least not for the time being.
