Destruction staff from Vateshran Hollows...
1st - it tethers through everything
2nd - it bugs many times and tethers over an infinite distance (once I was tethered all the way from Alessia wall to Alessia lumbermill)
It's not normal that it works through walls and bugs on infinite distance.
It also serves as targeting feature, it's simply a wallhack.
You can see that for example here, tethered straight through textures up from top of the wall tower, down to ground level at Alessia.