Rishi Eel

The Rishi Eel is a non-sapient, three-meters long predatory creature native to the rocky caves and canyons of the Rishi Moon, a moon orbiting around planet Rishi, after which the entire Rishi Maze Galaxy was named. Rishi Eels are dreadful predators with ten red eyes (two large eyes, each surrounded by four smaller ones) a four-jawed mouth and strong body armor. Their blood is blue-colored, indicating the presence of hemocyanin. The blood of Rishi Eels is also known for leaving stains virtually impossible to remove.

History
During the Clone Wars, a Rishi eel killed and ate the clone trooper rookie known as Cutup. An eel, possibly the same one that ate Cutup, was shot and killed instantly by Captain Rex, after receiving an expertly aimed shot through its eye and into its brain. He then marked the "shiny" armor of Echo with the animal's blue blood. Since Rishi eel blood was almost impossible to remove, the marking became permanently emblazoned on the rookie's armor.