I came across one in a random event, apparently, where some Super Mutants were patrolling and then they got into an engagement. I was watching from behind a hill, a Mr. Gutsy and an Assaultron engaged a group of 3-4. I was hoping to salvage a bunch of military tech from the aftermath, but then I saw this red glow.
It was like Cyclops taking off his visor. A beam of brilliant red carved out a section of the wasteland, illuminating the area like daylight. The four Super Mutants were gone in an instant, broken down into mere component particles. Then the Assaultron looked at me.
I'm really not a fan.