Sometimes, when enemies die, Arc Lightning stays active the entire time even when the enemy’s body despawns, this causes (on your screen) the animation to play as you continue to get farther away from the body. This is remedied by casting the spell again and waiting for it to be done, but this shouldn’t happen in the first place.
* (A strange light fills the room. Twilight is shining ahead. You’re filled with, DETERMINATION.)