Electric is an effect in Super Smash Flash 2 that is dealt by certain moves. Whenever a character is under the electrical effect, it will be tinted blue, and sparks will come out of the character. Additionally, for certain characters and moves, their skeleton will be shown.
Luffy is the only character in SSF2 to not show a complete skeleton when he is electrocuted. Since he is almost entirely elastic, his skeleton will only show a slab of meat with a bone sticking through it.
Some moves in SSF2 seemingly use electricity but they do not deal electric damage. An example of those moves is Sora's Thunder.