Spider-Ham’s origin story:

Peter Porker was born a spider and resided in the basement lab of May Porker, a scientist who invented an atomic-powered hairdryer to revolutionize the hair care industry. After dousing her head with water and activating the dryer, May accidentally irradiated herself and in a fit of delusion, bit Peter, transforming him into an anthropomorphic pig. Running from the Porker home, Peter soon came to realize that he still retained a spider’s abilities.

Spider-Ham was a spider bitten by a irradiated pig…

Source: Wikipedia