Cross-Species are genetically altered humans that have been somewhat (varies by person) turned into numerous creatures, respectively. These creatures have extremely enhanced abilities; abilities normal humans do not possess.
The first cross-species introduced to New York was Peter Parker, otherwise known as the masked hero Spider-Man. He was bitten by a genetically modified spider to gain spider-like powers. Next, Dr. Curt Connors of Oscorp Industries decided to create a lizard serum to attempt to regrow his missing limb. This caused him to transform into a giant lizard and terrorize Manhattan. In the video games, it is stated that Spider-Man is the only perfect example of a successful, healthy Cross-Species.
After the Lizard incident, Connors was thrown in the Beloit Psychiatric Hospital and Oscorp further worked on Connors' research and accidently started a virus outbreak when Peter Parker entered Oscorp Tower. This created multiple fearsome cross-species such as Vermin, Rhino and Nattie. To stop the infection and cure the people of New York, Doctor Alistaire Smythe of Oscorp created multiple robots to track down all cross-species and eliminate them; this would include Spider-Man. Therefore, the robots were soon called "Spider-Slayers" by Smythe.
Eventually, Connors had to return to the Lizard to help him fend off the haywire-gone Slayers to protect the city. However, the Lizard's reptillian mind took over and forced Connors to become a monstrous giant once again. Spider-Man soon stopped him, Smythe and his robots, and the whole cross-species virus. He used one of Smythe's flying bots to spray the antidote across the city, which helped clear the people of the infection much faster.
The equation that Peter Parker [spider man] gave Dr Connors was also a step further to tells spider man [Peter Parker] that even though he was bitten by a spider he could, like Dr Connors, take transformation into a spider so spider man [Peter Parker] has to be careful.
As of now, Spider-Man still roams the streets and cityscapes of New York and the Lizard (as Connors) is locked up in the mental institute with his path to redemption now beginning. Vermin's, Iguana's, Scorpion's, Rhino's and Nattie's whereabouts are unknown. All of the fully infected civillians, including Nattie's Pygo minions, have been eventually cured or died before a cure could be found. Dr. Mendel Stromm was one of the many who were infected with the virus, but his case was much worse than many's. His true status is unknown, but it is presumed he has died. Doctor Smythe committed suicide, not allowing himself to fully turn into a cross-species (he was not able to acquire the cure), and Gwen Stacy was cured and now lives with Peter in his aunt's friend's, Stan's, apartment.
- Peter Parker (Spider-Man) (controlled)
- Curt Connors (Lizard) (temporarily controlled, cured)
- Edward Whelan (Vermin) (presumably deceased)
- Iguana (deceased)
- Nattie (deceased)
- Unnamed Infected - (deceased or cured)
- Pygos (presumably deceased)
- Alistaire Smythe (deceased)
- Gwen Stacy (cured,deceased)
- Unnamed New York Civillians (cured)
- Unnamed Oscorp Industries Scientists (deceased or cured)
- Dr. Mendel Stromm (presumably deceased)
- Aleksei Sytsevich (Rhino) (presumably deceased, video game only)