The Feldip weasel is actually a kebbit, not a weasel. A player would have to track the Feldip weasel with a noose wand from their burrow. They are not seen roaming about like other kebbits such as the wild kebbit. However, players see them when pulling them out with a noose wand.
This monster lives in the jungle west of the crimson swifts, south of Feldip Hills. It is easier to find them if players find the hunter master there and go south from there, or just look directly north of the Oo'glog lodestone.
Noose wand
