Warning: contains spoilers for Savage Spider-Man #4!
Marvel's Spider-Man finally turns evil - by copying Reed Richards' cold, analytical mind and eschewing all previous attachments to the human race. Peter Parker, perhaps due to his true identity containing many flaws, is one of the more human characters in the Marvel Universe; his relatability comes from his compassion (even as he continues to act in a selfish manner with no regard for the consequences of his actions). But just like the leader of the Fantastic Four, Peter Parker finally loses what makes him human in Savage Spider-Man #4 - oddly enough, by ridding himself of his 'animalistic' side.
In the since-canceled Non-Stop Spider-Man series, Peter Parker investigated a conspiracy that included captured overachieving students (who all happened to be minorities) and a highly-illegal drug ring. Eventually, Peter discovered the culprit: Baron Zemo, who, following his Nazi ideologies, sought to "purify" the world and steal the intelligence of other geniuses at the same time. Unfortunately, versions of the drugs have a horrific side-effect on Spider-Man; Peter Parker is stripped of his human intelligence and becomes a monstrous human-spider hybrid in the current series Savage Spider-Man.
This Spider-Peter form is short-lived, for in Savage Spider-Man #4, written by Joe Kelly with art by Gerardo Sandoval, Peter becomes entirely analytical in a massive departure from his Savage Spider-Man form. His compassion is all but erased and he easily predicts Zemo's every move, outfighting him using his genius intellect. But Spider-Man shockingly does not stop Zemo's attempt to disperse the drug to the public from above. Instead of destroying the machines responsible, he elects to control them. "Ego, as a wise man once said, is the front of all suffering," thinks Spider-Man as he enacts his plan. "Hypothesis: eliminate the ego...eliminate suffering."
Peter Parker may be acting out of character, but as his animalistic, "primal" side was removed, so too was his empathy; he is willing to let hundreds of thousands of people die to save the rest of the population of Earth. This is a cold calculation for which Reed Richards is usually known, and indeed the recent Fantastic Four: Reckoning War contains many instances of Richards manipulating others for the good of the universe, even if he may appear cruel and uncompromising.
Thus, Peter's animalistic side holds back his supreme intelligence from compromising his ideals and emotions. Without them, he becomes a walking supercomputer with the capacity to save the world...even if it means the deaths of countless innocents. Spider-Man's metamorphosis into an uncompromising version of Reed Richards will hopefully never occur again, for if it does, the Marvel Universe may not be ready for it.
Marvel takes Spider-Man to the darkest of places by turning Peter Parker into a diabolical Reed Richards clone - with zero empathy or kindness.Joshua Isaak