For Sees All1: Level 136 Deadly Red Spiders 91/91/91 stats, with combat level 185 Using rune mace (crush weakness) and melee abilities conservative estimate of 10k xp per 5 min extrapolated amount comes to a maximum 120k/h The problem? It gets boring altogether too fast to bother paying attention. The spiders also drop nothing. Security spiders have considerably lower xp gain, cut at roughly half the 50k/h rate, if not even lower. Other stuff: If Jagex does not allow F2P to make cosmic and law runes in dungeoneering post-EOC, it would be best to bind cosmic runes in the ammo slot. Shades in dungeoneering are weak to crush. Most everything else is weak to some type of spell or another. The latter is also true outside of Daemonheim, as the F2P area is populated with undead. Tanglegum staff (the one usually turned into water) has all 4 elemental types. The death rune's only use in F2P is to teleblock. Chaos is useful in the curse spell which boosts your damage by 5%.
