The Iron Spider Armor is a suit players can unlock in the "Turf Wars" expansion for Marvel's Spider-Man. It is unlocked after completing Bring the Hammer Down, the final mission in the DLC's campaign. It does not possess an associated suit power.
The Iron Arms suit power (unlocked with the Iron Spider Suit) has a special look only with this suit.
The armor is based on the Spider-Man suit introduced in the pages of Amazing Spider-Man #529, where it is built for Peter Parker by his friend and teammate Tony Stark. It is mostly known for its appearance in the "Civil War" crossover storyline.