Ben 10 (Pre-Production)

Pre-Production applies to every decision, characters and aliens that were made before Ben 10 started. In 2004, Steve E. Gordon created his first concepts of Ben Tennyson and the Omnitrix; however, back then, aliens weren't involved. Gordon's first batch of concepts involved Ben, the Omnitrix, and ten human superheroes. Cartoon Network didn't like the concepts, as they just seemed like DC or Marvel superheroes.

Some time later, Gordon updated his concepts. The heroes would still remain mainly humanoid but they would look more like monsters, animals, and some of them, aliens.

Eric Canete, who also worked on Ben 10: Alien Force, was approached. His designs was more monster based and creepy looking, none of the transformations have visible Omnitrix symbols, Ultimately, the designs was rejected due to Cartoon Network thinking that they were not appropriate for children.

In 2005 Dave Johnson became the art director. He took a different turn on the idea, and, with Man of Action, they made the heroes aliens. Most of Johnson's concepts were immediately approved with slight changes, but some of them had be changed drastically to convince Cartoon Network.

Ben Tennyson
Ben is slightly taller than the finished version, with a different body type. He has red hair with a different haircut and wears a medium-sleeved, orange and white shirt with an orange collar. He has yellow eyes, black eyebrows and slightly pointed ears. He has a fair complexion and he almost looks pale. He has baggy, olive toned dark yellow pants with two huge pockets. He wears white shoes with that are light blue around the bottom and grey on the top and the sole.

On his promotional art, he wears the Omnitrix on his left arm. However, rather than resembling a watch, the Omnitrix is a yellow orb with holders. On the Omnitrix's promotional art, Ben wears it on his right arm and it actually resembles a watch.

Gwen
Gwen was originally meant to be Ben's classmate, not his cousin.

Omnitrix
This Omnitrix resembles more to an Earth watch. It has a grey case protected with a black material. The lugs are light and dark brown, the crystal is yellow and the crown is orange. It only has one big red hand that can be moved with the crown to select an alien out of the ten orange circles that take the places of the numbers. It also has two yellow buttons that have the same function as the green buttons on the finished version; raising and lowering the dial.

Omnitrix Aliens
Unlike the finished versions, the pre-production aliens were all humanoids, based off of classic superheroes. They all had one main power which was usually an element (fire, water, etc.) or a skill (intelligence, strength, etc.). With the exception of Greymatter, none of the aliens had a visible Omnitrix symbol.

Diamondhead
Diamondhead originally was the first alien to be unlocked in the Omnitrix.

Digger
Digger was replaced by Wildmutt but his digging abilities weren't implemented in any of the original aliens.

DragonFly
DragonFly is the pre-production version of the flying alien that was replaced with Stinkfly.

Ghostfreak
Ghostfreak is the pre-production version of the alien with the same name.

Greymatter
Greymatter is the pre-production version of Grey Matter.

Greymatter is based on the stereotypical Area 51 alien as it has grey skin, a huge head with giant, pupilles eyes. He has nasal cavities instead of a nose and stripes on his neck. He wears a black full-body latex suit that covers everything up to his chest. His torso is remarkably small and it is only a half the length of his extremities. He has a small tail, four fingers and three toes, two on the front, one on the back.

He wears the Omnitrix on his left wrist. He is the only pre-production alien that has a visible Omnitrix symbol. It has the look of a long, orange wristband that has three yellow orbs, one big in the middle and two smaller at the ends.

Inferno
Inferno is the pre-production version of the fire alien that was replaced with Heatblast.

PlantGuy
PlantGuy is the pre-production version of the plant alien that was replaced with Wildvine.

PlantGuy has an arboreal appearance. He has a green body that is seemingly covered with crust. His body has wrinkles, he lacks teeth and has a dark green tongue. His eyes are light green with black pupils. He has two long leaves coming out of the sides of his head, these leaves give the impression of ears. His crusty cover is wrapped over by multiple brown roots. He has five fingers that he can turn into roots and a long feet with two toes. He has a large, light brown collar raised up around his neck.

Razorjaws
Razorjaws is the pre-production version of the aquatic alien that was replaced with Ripjaws.

Razorjaws resembles a bipedal crocodile but with major detail changes. His body is colored with two shades of purple, and has dark green hieroglyphs all over on it. He has a long dorsal fin stretching from the top of head head to the middle of his back. The fin gradually becomes lighter in color on the top. His arms aren't bulky but muscular while his legs are rather slender. He has three giant gills on both side of his face making it look wider than it actually is. He has two yellow, green-pupilled eyes on the front of his face, a back-folded nose and a huge underbite. He has yellow teeth randomly scattered in his mouth.

StrongGuy
StrongGuy is the pre-production version of the strong alien that was replaced with Four Arms.

StrongGuy's most conspicuous feature is his four arms. He has a light grey body and wears a teal suit that reaches the middle of his limbs. The suit has teal knee pads, with a copper-colored jockstrap and six pipes that wrap around his shoulders and armpits. His face and arms have symmetrical, purple markings. He has three fingers on each of his hands and two toes. He apparently has no eyes or nose. He has a big chin and animalistic ears on the front of his face.

He seemingly wears the Omnitrix on the middle of his torso.

Upgrade
Upgrade is the pre-production version of the alien with the same name.

XLR8
XLR8 is the pre-production version of the alien with the same name.

Four Arms
Four Arms' design was the first that got greenlit. The final design doesn't differ from the early sketches.

Heatblast
Heatblast had to be re-designed a lot of times to get approved.

Stinkfly
Stinkfly's early sketches got vetoed and Dave Johnson had to go with a design that he hated and was harder to animate as well.