What is the G-Serum and what role can it play in the Osborn Legacy in Marvel’s Spider-Man 3?

**Major spoilers ahead** towards the end of Marvel’s Spider-Man 2 for PS5 which could tease the Big Bad for a potential sequel that may have ties to the Osborns.

Marvel’s Spider-Man 2 gave us an endearing, challenging, and ruthless villain in Sergei Kravinoff aka Kraven the Hunter and his army of Hunters (setting up Chameleon), and provided us a compelling and insidious baddie in Venom, also retelling one of the legendary arcs from Marvel which is both the Symbiote Saga and the Osborn Legacy.

Unbeknownst to Peter Parker and Mary Jane-Watson, Harry Osborn inherited his late mother’s disease of Oshtoran Syndrome and experienced complications. When his condition became critical, his father, Norman Osborn, placed him in stasis while he searched for a cure.

It is revealed that Harry became a host of the Venom symbiote, an organism of extraterrestrial origin that was a part of Dr. Curt Connors’ research. It attached itself to Harry and healed his condition so long as he continued to wear the symbiote. He then started a foundation in both his mother’s and Peter’s aunt’s honor called the Emily-May Foundation.

When Miles Morales got through to Peter in ridding the Venom symbiote before he succumbed to its influence, it chose Harry as its host once more and became the hulking, fearsome, monstrosity known as “Venom”. Peter defeated Harry with the help of Miles with the Anti-Venom Suit and destroyed the symbiote, rendering Harry comatose.

Enraged at Harry’s condition, Norman blamed the two Spider-Men and constructed his top scientists at Oscorp to prepare the “G-Serum” for human testing with his son, Harry being that very test subject.

Marvel G-Serum explained

If you follow the webpage associated with the Spider-Man videogame franchise developed by Insomniac Games and published by Sony over at Fandom, it listed the G-Serum as an experimental formula created by Oscorp. For those who are very much aware of the Spider-Man lore, they caught on immediately.

The “G-Serum” foreshadowed the appearance of Spider-Man’s greatest enemies to date besides Doctor Octopus and Venom, yes Marvelites that indeed the Green Goblin. The G-Serum refers to the Goblin Serum or Goblin Formula, and in some iterations, particularly, the Earth-1610 continuity as “OZ”, but it’s generally intended to heal the user or provide soldiers that are stronger in combat.

Created by Stan Lee and John Romita Sr., with the character of Norman and his alter-ego, the Green Goblin co-created by Steve Ditko (appearing in Amazing Spider-Man Vol.1 No.14) with his civilian counterpart having first appeared in 1966’s Amazing Spider-Man Vol. 1 No.37, the G-Serum was designed by Dr. Mendel Stromm, but Osborn framed him for embezzlement, took all his notes on the formula and recreated it himself.

The G-Serum is capable of granting the user enhanced strength, agility, speed, reflexes, durability, and intelligence but at the cost of one’s insanity. With the stage already being set ever since 2018’s Spider-Man with the appearance of not only the genetically modified spiders, but a prototype mask, the only thing left is the glider, bombs, and other goblin-themed weaponry.

What could happen to Harry Osborn?

Currently, the status of Harry at this point is he is being prepped to receive yet another treatment for his condition as he is practically on life support. What I believe may happen to Harry is one of two things: either Harry is too far gone to receive the G-Serum or it is that very serum that ends his life and is that loss that prompts Norman to go on the path to becoming the Green Goblin.

Harry already became Venom, so having someone like him become another threat would just be a repeat of Spider-Man 2 and will take away from Norman’s story arc if two Goblins are roaming around the city. Even if they kept Harry alive and inert, the focal point would be Norman who has been built up as the overarching bad guy up until this point.

How the G-Serum can fit in with Osborn’s Legacy

The G-Serum can be described as either a pharmaceutical drug in liquid or gaseous form or a performance enhancer for military application. Its exact nature depends on which adaptation or part of the Spider-Man mythos the writers and designers draw inspiration from. However, the version of the serum that Norman created specifically for Harry may be an improvement of an imperfect serum virus known as GR-27, also called “Devil’s Breath“.

This virus was discovered to have many applications, including self-healing. What if the G-Serum had a delayed effect on Harry’s body, enough to stabilize and extend his life, but not enough to fully treat him? This could have motivated Norman to create a derivative version of the G-Serum that he wanted to perfect. Without any worthy human trials, he may have decided to test it on himself out of desperation and hubris, which led to things going awry.

After Norman Osborn transformed into the Green Goblin, the G-Serum would have been kept by any surviving member of the Oscorp board while Norman was imprisoned for his crimes. However, if there are individuals in this universe who have connections to the Osborn lineage or are trusted allies of Norman, such as Donald Menken, Alison Mongrain, Lily Hollister, or Phil Urich, they may have possession of the serum instead.