Herbert Landon is a scientist and the C.E.O. of the Brand Corporation. He had a deep hatred for mutants and once attempted to destroy them. After Landon was turned into a mutant himself he began working for the Kingpin.
Herbert Landon founded the Brand Corporation and was it's C.E.O. Landon eventually hired Hank McCoy to work for him and McCoy developed a formula to cure himself of his mutation. However, the formula backfired and instead made McCoy mutate even further and grow blur fur all over his body.
Plot to destroy mutants
Several years later Landon developed a hatred for all mutants and was able to recreate McCoy's formula but was also able to change the formula to where it could destroy mutant DNA. The Kingpin bankrolled Landon's research believing that Landon would create an army of genetically altered super mutants under his control. Kingpin was of course obilvious to Landon's true ambitions.
The Hobgoblin soon learned of Landon's hidden agenda and began extort him for money or else he would leak the information to the Kingpin. One night Landon met Hobgoblin in a warehouse and gave him a briefcase full of money. As Landon left the warehouse he activated a bomb in the briefcase and blew up the warehouse. Landon believed that he had killed Hobgoblin. However, Hobgoblin somehow survived and swore that because of that attempt on his life the price of his silence wet up.
Landon later held a press conference to unveil his "mutant cure." However, he was attacked by Hobgoblin. Peter Parker was in the audience at that time and quickly changed into his Spider-Man costume and was able to save Herbert Landon's life but Hobgoblin was able to get away.
Landon then sent his men to spy on the Xavier Mansion and capture a mutant for him to test his formula on. The mutant they captured just so happened to be Beast. As Beast was brought to the Brand Corporation he learned that Herbert Landon was behind his abduction and he learned of Landon's plan to kill all mutants on Earth.
By working together Spider-Man and Wolverine were able to save Beast. However, at that time Hobgoblin broke into the Brand Corporation and was able to download all of Landon's research on mutants onto a disc and erase all mutant research from his computers. As Landon attempted to kill Hobgoblin, Hobgoblin revealed that he had all his research and told Landon that he would give it back to him for the right price. As Landon leaped into the air he grabbed hold of Hobgoblin's glider and as they flew over the vat of chemicals. Hobgoblin then dropped the disc and without thinking Landon dived after it and fell into the vat of chemicals. Hobgoblin believed that Landon was dead and escaped knowing that his chance to make a profit was gone. As Spider-Man, Beast, and Wolverine looked at the vat they wondered what the chemical would do to a normal human when it was designed to kill mutants. The three of them got their answer when Landon emerged from the chemical vat and mutated into a giant, green, reptillion mutant. Landon then began to absord electrical energy from a near by computer and Beast discovered that Landon must now feed on electricity or else he would be in constant pain. Landon also took his assistant, Genevieve hostage and broke out of the Brand Corporation and made his way into New York City. Beast and Spider-Man then realized that if Landon were to drain all of New York City's electrical energy he would grow to an immense size and become unstoppable.
The X-Men soon learned of Landon's rampage through the city and quickly responded to help Beast, Wolverine, and Spider-Man. Spider-Man and Beast quickly devised a plan to drain Landon of his bio-electrical energy to stop him and Beast revealed that the X-Men had the necessary equipment to accomplish this on the Blackbird. While Storm distracted Landon, Gambit was able to rescue Genevieve and get her to a safe place. Rogue then flew out of the Black Bird and wrapped a metal cable around Landon. As the Blackbird rose into the air Landon was was suspended in the air by the cable. A device on the Blackbird was then activated which was able to drain Landon of his energy. After this Landon transformed back into a human. However, half of his body was still reptilian. Landon was then taken to the hospital. No charges were apparently brought up on Landon and he remained a free man.
Turning Alistair Smythe into a Spider Slayer
When Alistair Smythe was caught betraying Kingpin by offering Spider-Man a chance to bring down Kingpin, Kingpin had Herbert Landon use his mutant formula to transform Alistair Smythe into a Spider Slayer. Landon then took Smythe's position as Kingpin's right hand man.
Spider-Man later tracked Smythe to Crime Central and the two of them fought. During their fight Spider-Man revealed to Alistair that Kingpin lied to him about his father being dead and that he was really being held in cryogenic suspension inside Crime Central. Alistair then went after Kingpin. However, Alistair's programming prevented him from harming Kingpin. Because of this Alistair attacked Herbert Landon instead. However, Herbert Landon and Kingpin were able to escape.
When Herbert Landon was transformed into a giant mutant he gained the ability to absorb electrical energy. Landon had to do this to ease his pain. By absorbing electrical energy Landon grew taller and taller until he was the size of a skyscraper. Landon could also fire the electricity at his opponents after absorbing it. After being transformed back into a human Landon lost these powers.
However, after Herbert Landon was transformed into a human half of his body remained reptilian. Landon had three claws on this mutated hand.
In the comics
Herbert Landon was an up and coming genetics researcher at Brand Corporation and a friend of Henry McCoy. After McCoy vanished (after growing fur due to a formula he created to cure himselfof his mutation), Landon became convinced Beast killed him.
As time passed, Landon worked more and more on research to create super-powers; his work earned him enough money that after the Brand Corporation closed he purchased the name (with the support of investors) and opened a new Brand Corporation with himself as C.E.O.
At an underground lab near LaGuardia, Landon and scientist Everett Burgos developed a genetic bath to remove mutant powers (this was changed in Spider-Man: The Animated Series to where it kills mutants).
At their Brand Pavilion, Landon hosted a mutation pavilion, announcing that Brand could merge human and non-human DNA, allowing them to mutate others at will. The Hobgoblin (Macendale) attacked the conference, and Beast and Spider-Man came to it's defense; both were captured by Brand personnel and Landon had them taken to LaGuardia for study. The Hobgoblin intervened, and Landon inadvertently fell into the bath, mutating into a rock monster form. He was captured and taken into custody; the ability to cure him uncertain.
In the comics Landon turned into a brown colored stoned monster. This was changed in Spider-Man: The Animated Series to where he was more reptilian and had green skin. Also in the comics Landon was never turned back into a human, while in Spider-Man: TAS, Landon turned back into a human and resembled the Batman villain Two-Face.