OZ is a fictitious artificial mutagen

Mutagen

In genetics, a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations cause cancer, mutagens are therefore also likely to be carcinogens...

 responsible for the creation of the Ultimate Marvel

Ultimate Marvel

Ultimate Marvel is an imprint of comic books published by Marvel Comics, featuring reimagined and updated versions of the company's superhero characters, including Spider-Man, the X-Men, the Avengers, and the Fantastic Four. The imprint was launched in 2000 with the publication of the series...

 Universe's Spider-Man

Ultimate Spider-Man

Ultimate Spider-Man was a superhero comic book series that was published by Marvel Comics from 2000 to 2009. The series is a modernized re-imagining of Marvel's long-running Spider-Man comic book franchise as part of its Ultimate Marvel imprint...

, and several of its other characters. The writer, Brian Michael Bendis

Brian Michael Bendis

Brian Michael Bendis is an American comic book writer and erstwhile artist. He has won critical acclaim for his self-published, Image Comics and Marvel Comics work, and is one of the most successful writers working in mainstream comics, with his books selling consistently highly for over a...

 decided that a genetically mutated spider would be the source of Peters power, rather than a radiated one, to update spider-man for the 21st century.

Origins

The OZ formula is created by Osborn Industries as part of their research into super soldiers for S.H.I.E.L.D.. Despite being imperfect, Norman Osborn garners much interest in OZ, while not revealing what it actually is. Osborn subsequently begins to fail, as it is unable to deliver on Normans promises. The drug is developed prior to Ultimate Spider-Man #1 and has begun animal testing.

Peter Parker (Spider-Man)

While on a science field trip to Osborn Industries Peter Parker is bitten by an escaped spider mutated with OZ. The OZ mutates Parkers blood.


The effects of the OZ treated spider venom manifest as:

• Enhanced Strength
• Enhanced Agility
• Enhanced Reflexes
• Enhanced Stamina
• Enhanced Durability
• Wall-Crawling
• "Spider-Sense", warning him of danger.

Osborn realises Peter was infected by the spider, and attempts to give himself powers using OZ.

The OZ Explosion

In the experiment Norman Osborn performs in an attempt to give himself powers, there is an explosion which exposes several people to OZ.

Norman Osborn (The Green Goblin)

The only person who was intentionally affected by the OZ (in this instance), Norman Osborn had it injected into his mainline as a solution of his blood. He may have caused the explosion with his new abilities.


The effects of the OZ treated blood manifest as:

• Ability to change to Goblin Form at will (discovered in the Ultimate Six
  Ultimate Six
  Ultimate Six is a seven-issue comic book limited series and crossover between Spider-Man and the Ultimates , featuring the Ultimate Marvel version of the Sinister Six...
  
  limited series. Prior to this OZ injections were used mainline)
• Greatly Enhanced Strength while in Goblin Form
• Enhanced Durability while in Goblin Form
• Super-Leaping while in Goblin Form
• Advanced Healing Factor
  Healing factor
  A healing factor is a term used to describe the ability of some characters in fiction to recover from bodily injuries or disease at a superhuman rate...
  
   while in Goblin Form
• Can throw Fire-balls while in Goblin Form

His Green Goblin persona appears as a green, slightly draconic goblin. He is originally only green in the face, but later "evolves" and gains full green coloration. He also appears to continue his mutation, becoming more in control as time passes, as well as increasingly lethal.

Otto Octavius (Doctor Octopus)

Norman Osborn's head scientist who uses a set of mechanical arms for multi-tasking and handling hazardous substances. In the initial explosion these arms are fused to his body. It is first thought that he controls only the arms, but this is later disproven. The OZ explosion grants Doc Ock ferrokinesis (the ability to control metal).

Harry Osborn (The Hobgoblin)

Harry Osborn was caught in the explosion whilst visiting his farther at work. There has not been confirmation of the OZ mutation being caused by the explosion, or during the Hobgoblin arc when he is led to a bunker containing OZ, or both.


The effects of the OZ exposure manifest as:

• Ability to change to Hobgoblin Form at will
• Greatly Enhanced Strength while in Hobgoblin Form
• Bullet-proof exoskeleton while in Hobgoblin Form
• Advanced Healing Factor
  Healing factor
  A healing factor is a term used to describe the ability of some characters in fiction to recover from bodily injuries or disease at a superhuman rate...
  
   while in Hobgoblin Form
• Can use limited pyrokinesis
  Pyrokinesis
  Pyrokinesis, derived from the Greek words and , was the name coined by horror novelist Stephen King for the ability to create or to control fire with the mind that he gave to the protagonist Charlie McGee in Firestarter...
  
   while in Hobgoblin Form, e.g.: self immolation
  Immolation
  Immolation, from Latin immolare, "to sacrifice", originally "to sprinkle with sacrificial meal" , in modern English since the 16th century may refer to:* Fire sacrifice** Holocaust * Cremation...
  
   and fire projection

The appearance of his Hobgoblin persona is somewhat similar to his father's Goblin persona, but is orange in coloration and far more demonic. If exposed to OZ further, his mutation will most likely continue, like his father's.

Mary Jane Watson

After the exposure to an unspecified quantity of the OZ formula courtesy of a clone of Peter Parker, Mary Jane becomes a similar being to the Osborns, except for long red hair all over her body. She is known as the Demogoblin The process left her with post-traumatic stress.


The Effects of the OZ infusion manifest as:

• Ability to change to Demogoblin Form when suffering from severe anger, stress or panic.
• Greatly Enhanced Strength while in Demogoblin Form
• Enhanced Durability while in Demogoblin Form
• Enhanced Reflexes while in Demogoblin Form
• Enhanced Stamina while in Demogoblin Form
• Powerful Claws while in Demogoblin Form

Mary Jane appears to be cured a short time after infection by Dr Franklin Storm. This cure is later seen wearing off, when her fingers turn to claws watching Peter talk to Kitty Pride.