Happy Halloween_Plumbline or Bait_x264

Happy Halloween everyone ! I saw this spider doing something strange with a piece of mulch, for some reason it had attached a spider-line to it and was slowly pulling it up to it's web ! When I first saw it the thing was hanging there in the air about 15 cm from the ground and 6 hours later when I recorded this video the spider had it up to almost 1 meter off the ground ! The only thing I can't figure out is why the spider was doing this. Is it using the much as a plumb-line for it's web or is it some strange kind of bait ?