This papercraft is Goku Super Saiyan 4 (SS4, SSJ4 or Super Saiyan Level 4), a Saiyan transformation present in the anime-only sequel Dragon Ball GT of the Dragon Ball series, the paper model was created by Carojama. This transformation is the ultimate combination of both the humanoid Saiyan and the Great Ape. The only way a Saiyan can attain Super Saiyan 4 is if he is already a Super Saiyan, can transform into a Golden Great Ape, and then regain conscious control over the form. After this form is attained once, it can be accessed at any point.
The Super Saiyan 4 form was designed by Toei Animation's character designer Katsuyoshi Nakatsuru.
In this form, the Saiyan's hair color differs, the same goes for the tail and the body is covered in red fur. A Saiyan in this form also possesses a shadow trim around the eyes and over the eyelids that varies in color, such as crimson. The hair is lengthened, but not nearly as long as a Super Saiyan 3's. The aura in this form loses the arcs of electricity and replaces it with sparkles and also becoming pure fire. In the case of the Fusion Dance warrior Gogeta, the coloration of the aforementioned features seemingly switch, as Gogeta's hair became a bright shade of red whereas his fur became a dark shade of brown and the trim around his eyes were black instead of red. The massive power and speed enhancements brought on by this form easily make it the strongest Saiyan form in the entire series.
For example, while Goku's Super Saiyan 3 form was almost unable to even faze Baby Vegeta, as soon as Goku transformed into a Super Saiyan 4, their roles in power became polar opposites, with Baby Vegeta being almost unable to hurt Goku at all. The users of this transformation have powerful signature techniques. For example, Goku develops an attack he calls 10x Kamehameha, as it is ten times stronger than the Super Kamehameha, while Vegeta, in his Super Saiyan 4 state, uses an attack he calls the Final Shine Attack, which is a more powerful version of his Final Flash attack.
Unlike the Super Saiyan 3's strain due to the utilization in ki, this form does not require as much energy consumption as Super Saiyan 3's, allowing the user to stay in the state at a much longer duration. It also appears that the form makes the individual larger in height and muscularity. In scenes with Goku standing next to others such as Gohan, Goten and Trunks, Goku appears much taller and bulkier than all of them, even though in his normal state, he is relatively the same size. A highly debated subject, many fans believe the Super Saiyan 4 form to be the true form of the Original Super Saiyan, first spoke of by Vegeta in the Namek Saga. Vegeta states in his monologue, that "the Super Saiyan could only maintain his maximum power in the transformed state". Also, Elder Supreme Kai appears to know of the Super Saiyan 4 form, cementing the thought that Super Saiyan 4 has existed before Goku attained it, most probably by a previous Super Saiyan. The Super Saiyan 4 form even has enough power to break through a wish made with the Dragon Balls, as it turned Kid Goku into an adult again.
The Super Saiyan 4 form was first achieved by Goku after transforming into a Golden Great Ape and witnessing his granddaughter Pan crying to calm him down. In this new form, Goku had enough strength to dominate Super Baby Vegeta, whose attacks had no effect on Goku. However, after Baby transformed into a Golden Great Ape, thanks to a controlled Bulma, things were far more even but despite Baby's new power. Eventually the two had a double Knock-out. Baby was rejuvenated by Bulma's Blutz waves however, Goku borrowed energy from his friends and family and gained enough power to defeat Great Ape Baby, and finally finished the Tuffle parasite with a powerful 10x Kamehameha, forcing Baby to flee Vegeta's body, and try to escape inside a spaceship. Just before Baby could escape, Goku fired a powerful Kamehameha wave up at the spaceship, hurdling Baby into the sun and finally killing the evil Tuffle.
Goku's next opponent would be Super Android 17, who had easily defeated the other Z Fighters, and who proved to be Super Saiyan 4's first real challenge. Because of his energy absorbing abilities, Super 17 was able to turn all of Goku's energy attacks into his own power, making him stronger with each attack. Eventually, Goku reverted to his base form and killed the android using his Dragon Fist attack followed by a Kamehameha.
Super Saiyan 4 proved to be incredibly helpful when Goku used it to take down most of the evil Shadow Dragons. However, he met his match in Syn Shenron, the strongest of the seven dragons, who had absorbed all of the Dragon Balls becoming Omega Shenron. Omega's power proved to be far greater than that of a Super Saiyan 4's, and Goku was thrashed around for most of the fight. Seeing how bad this situation had become, Vegeta used Bulma's Blutz Wave generator to grow a tail without having to wait for it to grow naturally. With a tail Vegeta was able to become a Golden Ape like Goku, and then when he finally gained control, he was successful in becoming a Super Saiyan 4.
However, even as a team, Goku and Vegeta still stood no chance against the dragon. It wasn't until they fused into Super Saiyan 4 Gogeta that their power finally surpassed Omega Shenron's. However, Gogeta spent too much time playing around with Omega Shenron and the fusion wore off in fifteen minutes due to his own tremendous power, and he ultimately failed to finish him off in time. Goku eventually killed Omega Shenron with the Universal Spirit Bomb. It is unknown if, with proper training, Goku and Vegeta could have become powerful enough to match Omega Shenron without needing to fuse, as the saga ends with Omega's defeat and Goku leaving with Shenron.
You can download the papercraft model here: Dragon Ball - Goku Super Saiyan 4 Free Papercraft Download [mediafire] [25 cm Version] [40 cm Version]