A charge like that of electricity runs through the body of a wizard with this automatic defensive spell.
References from the canon
- When Vernon Dursley tried to hold Harry around the neck, he felt a sudden charge like electricity running through Harry and he had to drop him. This appears to have been an automatic defensive response on Harry's part, since there is no indication that he intentionally cast a spell (OP1).
- Dumbledore used a similar spell to make Umbridge let go of Marietta, whom she was shaking violently. This may be a different form of the spell, however, since Dumbledore used his wand to perform it (OP27).