Not sure if Nex drops it or what but when I was doing Ancient Creatures task I receive Guthix Arrows. Would be rational to have a bow to fire them - Guthix Bow.
Adding it to Armadyl Boss(Kree'arra) droptable.

This isn't so needed I'm just bringing it up back again:

Making Jungle Strykewyrm(Requires 73 Slayer) which could be place south of Emps-Wars and Go'Oolog City and has same mechanics as Ice Strykewyrm just with lower defence and attack bonuses(any style). Jungle Strykewyrm droptable could be similarity of its succesor just instead of rune bars - adamant, crushed nests - wine of zamorak or potato cactus.
Unique drop - pet: http://runescape.wikia.com/wiki/Freezy that could be obtained only through Jungle ones. After killing 200+ of each Strykewyrm(Ice and Wildy) you could have ability to buy from Slayer Shop another one Freezy(Wild) or Freezy(Ice) glowing around it would be same as elemental items/whips with crystals.