A plumber's Electric Eel also know as "Sewer Snake" or"Toilet Jack" is a flexible auger or drill like tool that is used to clean out and remove blockages from from within waste pipes, drains and sewers.
Most devices consist of a coiled metal wire with some space between the coils at the end so that it look similar to a corkscrew. The other end has a crank or an engine that causes the corkscrew to spin.
Improper or unskillful use of an auger can easily break plastic or copper pipes. DO NOT ATTEMPT TO OPERATE ONE UNLESS YOU KNOW WHAT YOU ARE DOING.
Alternatively there is a new technology that causes no damage to pipes. The JetRod uses high pressure water jets to clear blockages. For more information click here.
The crank or engine spins the drill or blade in a clockwise direction into the blockage allowing the retrieval of objects such as hair, combs, small toys and cloth. If the blockage is not retrievable the electric eel can also break up blockages such as tree roots, foam and plastic objects.
If the pipe is not completely blocked but the flow has been reduced by a blockage, the eel flails around this inside of the pipe scraping off accumulated matter than con constrict the flow by reducing the diameter of the pipe such as mineral deposits or grease.