Confusion is obvious. But you answered the nonexistent question. So, wtf is the crater from? & the fact that the alien ammo is everywhere led me to think this was firelance....
Does the firelance stand out on the ground like the alien ammo does at night?
That huge crater is a mystery.... and there ARE energy cells in there, but they are not related to the event, unless of course it happened there. Firelance is brutal to find, as it is the same color as the brown ground. I do it bobby-style: imagine a grid, and slowly go back and forth. If you have Dogmeat as a companion, he will find it for you. I have had the event before, never found the weapon (but did find all the ammo), went and recruited Dogmeat then went back and successfully found the weapon. Mark the area on your local map with a custom marker.
The last time I had this event, I was easily able to find it, as all I had to do was kill the raider who nearly killed me with it. :sadvaultboy: