Can be used in combination with Earthbind and/or Brambles to reap the benefits of the knockdown.
The spirit's attack inflicts 0 damage, which is considered damage for the purposes of skills and effects that trigger when the target takes damage.
"Stationary" includes targets that are attacking or activating skills. A target must actually be moving its position within the world in order to avoid the knockdown.
When used with Earthbind, the spirit's attacks trigger at such a point that the foe will be incapable of standing long enough to move after the knockdown. So long as both spirits have health and Wanderlust continues to attack that enemy, the foe will be completely unable to perform any action other than skills with instant activations.