The Giant
Spider was a mutant
Spider which developed accidentally through consuming the
t-Virus during the Raccoon City outbreak. It is unrelated to the
Web Spinner which an early B.O.W. (Bio-Organic Weapon) created by Umbrella under laboratory conditions.
The Giant
Spider grew to around twenty times the average size and they also became fairly heavy with the power to knock down a fit and healthy human. They also had a potent venom which could poison their target. Fortunately the
Blue Herb was a reliable cure. They could also produce small Spiders from their abdomen which they could launch as a deterrent but they also swarmed from their bodies after death.
They infested the sewer system of Raccoon City and unlike the
Web Spinner - the Giant
Spider could in fact produce webbing making them in fact a better predator than their lab-created cousins.
Dr
James Marcus also experimented with early
t-Virus samples and spiders which the resulting creation he also called the Giant
Spider (named Giant
Spider Zero for the
Wiki) - although these two are not directly related. Like the
Web Spinner, these cannot produce webbing.