Warden's Cloak

Specially constructed for the night elves' wardens, these green velvet cloaks bear a fringe of deadly, razor-sharp blades along the hem, resembling the wings of an owl. Wardens learn to shift and swing the cloak dramatically, presenting the blade finges to anyone who might get too close. The cloaks is both a defensive measure against sneak attacks and a potent weapon for the warden when surrounded by enmies. It also provides numerous knife blades for the warden to use.

Source
This item drops from level 36-40 mobs in Kalimdor.