Dr. Miles Warren taught both Peter Parker and Gwen Stacy during their college years, but became obsessed with the latter and went insane upon her death at the hands of the Green Goblin. That led to the deranged biology professor attempting to clone them both, something which decades later would lead to the convoluted/controversial "Clone Saga". Jackal isn't as iconic as many of Spider-Man's other villains, but the impact he's had on the character's life has been huge. One of Peter's clones - Kaine - currently serves as the Scarlet Spider, while Warren played a key role in the "Spider-Island" story arc, helping to give all of New York's residents spider powers before transforming them into mutated giant spiders!