With a tip of the hat to Jeff Mejia of Evil DM Productions for his work on the BoL version of Legends of Steel, I present the Giant Spider (Tlactoztol variant).
Eight-legged death awaits the foolhardy in the jungles and ruins of Tlactoztlan in the form of giant spiders the natives call Hueyatocatl. These malevolent creatures possess a deadly poisonous bite delivered with terrible mandibles. Look carefully before you step into that darkened room or seemingly innocent clearing, traveler.
Hueyatocatl poison causes nerves to burn with a searing agony as it courses through the veins of the unlucky victim. Immediately after being bitten the victim must make a Hard Strength-based task check or take an additional d6 damage that bypasses any armor or other protection. Subsequent bites in the same encounter do only an additional d3 damage unless a Tricky Strength-based task check is made.
Attack with Bite +1; d6 + poison
Protection: 1 (chitinous hide)