Yeah, it’s super nasty stuff… From memory, its burning because of a chemical reaction, it isn’t ignited as such. This means it burns far hotter (and so passes through building materials better) and can’t be put out via water/smothering, etc…

This is precisely why is a war crime to use, because it indiscriminately kills everything. I may be a bit rough on the details, but you get the idea!

I’m guessing this is white phosphorus? Pretty to watch from a distance, terrifyingly if you’re in amongst it.