I just got Arachas Venom and Arachas Mutagen to drop from the Contract "Missing Brother". It is labelled as Level 33, but I'm only Level 26 (it had the Red Skull of Certain Death) and I have beaten it at Level 19 before (using a lot of Yrden Shock Traps and Dragon's Dream + Dancing Star {I forget which level of bombs}); this time I used 3 of each Superior Bombs and Superior Insectoid Oil on a Deargdeith sword 286-350, Level 22, with 3 x Greater Chernobog Runestones = +15% Attack Power giving base damage of 328.9-402.5 or approx. Lvl 27, +13% Aard, Yrden & Axii, +4% Bonus Experience From Humans & Nonhumans (DOH!!!), which was also enhanced by a grindstone in Mulbrydale before I set off (at full gallop on Roach to get there with as much time left on the sword and armour buffs as possible); my other main tactic was Superior Golden Oriole which heals Geralt whenever the Arachas tries to poison him and, considering that poison is its' main strategy, that is pretty often, LOL! Combined with frequent use of Quen and Robert is the man having an affair with your mother...