The Mon Cala eel, alternatively referred to as the Mon Calamari eel or the electric eel, represented a predatory eel species native to the oceans of Mon Cala. A notable characteristic attributed to them was their slipperiness.
The initial appearance of the Mon Cala eel occurred in "Prisoners," specifically the third episode within the fourth season of the Star Wars: The Clone Wars television series, which debuted on September 23, 2011. The designation of these creatures as both Mon Cala eels and electric eels originated from the episode guide featured on StarWars.com. Their identification as Mon Calamari eels was first established in the 2015 publication titled Dark Disciple.
George Lucas put forth the idea of utilizing the eels as a form of confinement, aiming to illustrate an alternative method for restraining Jedi. Prior to the "Prisoners" episode, The Clone Wars had exclusively depicted their containment through the use of an energy field. The design of these eels was the work of artist Carlos Sanchez.