I will try and remember, its mainly from reading Youtube comments on some old video's its kind of an Urban Legend.

Just did a search there are some videos, don't know how true it is, but it is very interesting!

Vietnam War Secrets: Red Night Vision Goggles, Demons and a Military Cover-Up

https://www.youtube.com/watch?v=8ClqmP69ERE&t=1s

I have never been on this website before, it just came up when searching for more info.

Did soldiers in Vietnam see demons in their night vision goggles?

The same questions always come up when I start talking about Dicyanin. People always want to regurgitate the urban legends they heard about Dicyanin on the internet. One of these stories is from years ago where somebody got on a podcast and claimed that during Vietnam there was a new type of night vision goggle that allowed soldiers to see demons and entities out in the jungle and it was driving them mad.

As much as this sounds like an exaggeration, I actually have some documentation here from the U. S. Naval Academy that indicates that is exactly what soldiers were reporting. The document is called, The Secret of Seeing Charlie in the Dark, by Richard A. Ruth of the Department of History of the U. S. Naval Academy.

He indicates that though they used the new scopes in the field and they offered a tactical advantage, the users who used them endured physical, psychological, and emotional stress unforeseen by military leaders. Now, why would an optical tool? Give profound psychological stress. Let's read exactly what he says.........

https://www.museumoftarot.com/post/seeing-demons-in-the-dark-red-night-vision-in-vietnam