Attempting a few of the abilities...
Silver Toxin (Ex): A victim bitten by a silver spider must succeed on a DC X Fortitude save or find its skin transformed into the same silvery matter as the spider. The victim is slowed (as the spell) for 1d10 rounds, but gains a +8 bonus to its natural armor. At the end of this duration, the creature is fully encased.
Once fully encased, the creature retains the natural armor bonus and is considered unconscious and needs no air or sustenance. It remains in this state for 24 hours, after which its skin reverts back to normal and it receives natural healing as if it had slept for an entire night. The victim's hair and eyes retain the silvery sheen permanently, and nothing short of a limited wish, wish, or miracle can restore their original appearance.
The transformation process can be slowed or halted before the creature is completely encased by a delay poison, neutralize poison, or similar magic. The save DC is Constitution-based. Creatures with immunity to poison are unaffected, and creatures resistant to poison receive their normal bonus on their saving throws.
Silver Web (Ex): A silver spider can throw a web up to eight times per day. This is similar to an attack with a net but has a maximum range of 50 feet, with a range increment of 10 feet, and is effective against targets up to one size category larger than the spider. The web anchors the target in place, allowing no movement.
An entangled creature can escape with a successful DC x Escape Artist check or burst the web with a successful DC x Strength check. The check DCs are Strength-based and includes a +4 racial bonus. The web has 15 hit points and hardness 10, and takes double damage from fire.
A silver spider can create sheets of sticky webbing up to 30 feet square. It usually positions these sheets to snare flying creatures but can also try to trap prey on the ground. Approaching creatures must succeed on a DC 20 Spot check to notice a web; otherwise they stumble into it and become trapped as though by a successful web attack. Each 5-foot-square section has 15 hit points and damage reduction 5/-.
A silver spider can move across its own sheet web at its climb speed and can determine the exact location of any creature touching the web.