For a while now i have noticed a that a BOS npc will spawn at random places around the map.

I have finished the main story line doing the Minutemen ending so that my character is on friendly terms with the BOS and Railroad.

Sometimes the npc is on top of buildings, sometimes at my settlements and I also saw one on the road.

The initiate can draw fire from foes but is immortal. If I try to attack it my blows pass straight through it without colliding with.

This hasn't really bothered me too much but I would like to turn the BOS hostile against me to get some extra action in the game.

The trouble is when I tried this and one of the immortal BOS turned up a never ending battle occurred between the settlers and the non-interactive BOS.

I am running the latest vanilla release with no mods.

Example of immortal BOS npc being continually attacked by synths whose gunfire pass straight through.

http://ocau.com/pix/0zaxd