Stinkfly is the Codon Stream's DNA sample of a Lepidopterran from the planet Lepidopterra.
Stinkfly's body is bug like and he has 4 legs with 2 arms. He seems to stand like a mosquito since he dosn't stand up straight. His eyes are tiny and yellow-orangish when he was 10. His wings are very fragile with lines on it. His limbs are a brown-greenish colour but his wings are light green. His body is white with black lines on the front that have dark black circles on the side and coming out of these black circles are his 4 limbs and his 2 arms. Stinkfly's hand is black as if he is wearing gloves and each hand has 3 fingers.
In the Ben 10 (Original Series), the Omnitrix symbol was on his forehead.
In Ultimate Alien, Stinkfly's Ultimatrix symbol is on his chest and he now has big pupils in his eyes and his eyes are much bigger.
In Ben 10: Omniverse, Stinkfly has clothes are now green and now spread only till his forehead. He has lighter skin the Omnitrix has returned to his forehead and he also has pupils and his body and tail are bigger.
11-year-old Stinkfly in Ben 10: Omniverse looks the same as in the original series just the Omnitrix symbol, his face and his eyes are green. He also now has pupils.
Stinkfly's wings allow him to move at high speeds in the air and dodge attacks just as quickly. Stinkfly also possesses disproportionate strength, enough to carry people and objects heavier than himself. Stinkfly's four eye stalks give him a wide range of vision from the sky, including the ability to look directly behind himself.
Stinkfly can excrete high-pressure streams of liquids from the pollen ducts in his eye stalks and mouth. The type of liquid can range from a flammable toxin to an immobilizing jelly. In Don't Drink the Water, Ben's child form of Stinkfly, Stinkyfly could emit a powerful herbicide gas through flatulation, it is unknown if older Stinkfly can do this. It is shown in the Forge of Creation, he shot a light blue beam when Ultimate Swampfire trapped Aggregor with his vines.
Stinkfly is weak to any kind of chemical poison or gas. Although his exoskeleton body is fairly strong, his wings are very fragile. Water is especially a problem for Stinkfly, as it can render him incapable of flight if too much gets on his wings. Furthermore, he is unable to swim due to the small surface area of his limbs. A minor inconvenience is Stinkfly's intense body odor, so hiding from anything or anyone that can smell can be a problem.
- Stinkfly was the first alien that Ben named on screen.
- Stinkfly was the first alien in the original 10 in the Original Series able to fly, with the second being Ghostfreak.
- According to Cartoon Network UK, Stinkfly's slime feels like a mix of rubber cement and warm oatmeal.