So, the idea of the coilhead is pretty simple, it's similar to the Weeping Angels from Dr. Who and Peanut from the SCP Foundation.
This is supposed to be a straightforward way to deal with the otherwise-invulnerable coilheads and more or less permanently remove them as an enemy if you do it right. Already we have the ability to do this to most of the invulnerable monsters, trapping them behind locked doors and blast doors.
Simply put, the way the mod works is as follows:
If two coilheads directly face one another, both of them are disabled unless someone walks between them to block their line of sight of eachother. This allows players to pull off the dangerous but effective tactic of luring both coilheads together and making them stare at eachother, disabling them for the duration of the moon.
Why do I think this needs to be added? Well, generally when you encounter a coilhead, all it means is that one person on your team has to go AFK and just stare at it.