Anthony Serba was Professor Miles Warren's gifted lab assistant at Empire State University.
Warren was at one point so overwhelmed in sadness over the death of Gwen Stacy which happened during a battle with Spider-Man and the Green Goblin months earlier, that he would do anything to bring her back. When Serba presented Warren with a successful genetically cloned frog specimen, Warren got the idea that perhaps Serba could help him in cloning Gwen Stacy.
Warren presented Serba with two seperate samples of genetic material, one from Gwen Stacy and the other from Peter Parker. Warren had obtained the samples earlier from a class experiment he had instructed his students to complete. Warren falsely informed Serba that the genetic material he presented Serba with was from a rat. Serba, ignorant as to what Warren had really given him, enthusiastically got to work.
Serba discovered four weeks later that the specimens he was cloning were not rats, but in fact, human. He frantically informed Warren, and suggested the clones be destroyed. Not wanting anyone to find out what he was up to and in order to preserve his clones, Warren brutally murdered Serba in a fit of rage. He later disposed of Serba's body in an incinerator.
Unable to come to terms with having been the one who killed Serba, Warren began developing a second personality which he dubbed the "Jackal" after overhearing a lecture on jackals. It was Serba's death that eventually led to Warren donning his Jackal persona, and eventual full descent into madness.
Warren later used his Gwen Stacy clone in an attempt at psychological warfare with his hated enemy, Spider-Man. He then used the Peter Parker clone in an attempt to rob Spider-Man of his very identity at Shea Stadium, which ultimately failed. Warren had later seemingly come to terms with and admitted to killing Serba, thus causing him in his seemingly final moments to nobly save Ned Leeds, whom Warren had attached to a bomb that only the true Spider-Man could deactivate. It was later revealed that the Warren who died was a clone the real Jackal had sent to die in his place should things go awry.
It was later thought that the Spider-Man clone from Shea Stadium was, in reality, Anthony Serba. It was believed that Serba had been infected with a genetic altering virus by Warren that remade him in Spider-Man's image. This was later revealed as a ruse by the High Evolutionary in an effort to discredit Warren, his former pupil.