OK a wolfstalker is a pure werewolf bitten by a pure nightstalker(nigthstalker full credit to kittyme123)

bad things-
they can't control the urge to change into a wolf
they can't control the urge to bite someone (or in the case of xander a tire.)

powers-
ALWAYS /one/ elemental power
mind control
super strength
super smelling
medium speed
super duper hearing

weaknesses-
wolfsbane
loud high pitch sounds
dragon silver(most effective)

Apperance when in 'wolf form'-

black hair. scars and stuff is the body and the eyes are ALWAYS green.

oh yeah only one person can bite them.Ivy.