Scarlet is an experiment created by Doctor Krekkarius using similar genetic blueprints to that of Stitch. It is because of this that Scarlet does not have an official number. He is a blood-red Grarrl/koala-like experiment with a very dark magenta claws, a frilly ears similar to Leroy, and gold-orangish skin on his belly, tail, hands, and around his eyes.
Scarlet is a antagonistic, intelligent, conceited, psychotic, cruel, brutal, vain, mean, and shapeshifting experiment who is Stitch's arch-enemy, with blood-red scaly and leathery skin instead of fur, a very dark magenta claws, a frilly ears with bright green insides, a gold/orangish-red stomach from his chin down and around eyes, dark reddish-brown markings on the back of his head and on his back, white crocodile-like teeth, a reptilian tail, and a slightly deeper voice as well as two extra, retractable arms, two bent retractable antennae on his head, three bent retractable spines on his back and retractable claws on his front and back paws.
Like Stitch, he is able to mutate into a second form with four arms, two long antennae, and three spikes on his back.