Lightning!Sans wears a yellow and orange hoodie, with orange shorts and an orange undershirt. His slippers are blue with a yellow line across the top. His left pupil is white and his right pupil is yellow (which may be caused by the lightning-like crack that comes down from the right side of his skull and into the right eye socket). It's advised nobody touches the lightning crack, as it will zap you.
If you injure Sans he will show his true potential, summoning what is assumed to be a combination of all of the human souls.