Always glad to help a fellow PS fan. The razorvine ain't much of a monster, so I guess it would be classified as a hazard in 3E. Doing a rough conversion, it would be a Large, plant hazard (12 ft-20 ft in diameter) AC 15 (-5 for no Dex, -1 for size, +11 natural), and say maybe 7 or 8 hp per vine with a Con of 14 or so. Razorvine only takes damage from slashing weapons, not blunt or piercing weapons. Those with slashing weapons without reach trying to cut the vine must make a Reflex save (Say 12 or 13) or take 1d4+ the sod's base AC as the razorvine instinctively lashes out cutting the victim with its sharp thorns and barbs. For this purpose, the victim's base AC is detirmined by his AC modified by armor, deflection and natural AC bonuses, but not Dexterity, shield or other adjustments that don't cover the whole body. Climbing, grabbing or otherwise touching the vine provokes the same reaction, but only for 1d3+base AC. Somebody stupid enough to fall in the stuff takes 1d6+base AC damage with no save allowed. The razorvine is also immune to non-magical fire and most "naturally" occurring environmental effects on the planes.