Nudjs were a species of lizard with green skin that inhabited the swamps of the planet known as Dagobah. During 3 ABY, as Luke Skywalker, a Jedi apprentice, went into the Cave of Evil, a nudj dashed from its opening.
The initial appearance of a nudj was in the 1980 original trilogy movie, Star Wars: Episode V The Empire Strikes Back. Their initial identification within established canon occurred in the "Every Creature in the Star Wars Movies" video, which the Star Wars Kids YouTube channel put out in 2019.