Shots can bounce from target to target
Each bounce (or arc) will lose a percent of the damage
The electric tower shoots eclectic balls that will bounce (arc) from one target to another, losing a percent of damage each bounce. The bounce will only occur with balls that are in range of the tower, so it's a good idea to spend some upgrade points increasing the range.
The electric tower Dark Power gives it a chance to shoot five bullets at any targets in range. This can allow for massive damage, as each shot will arc between different balls separately.