First time I also came across it was from Angels and Demons, I pondered about the possibilities of existence of such a phenomenon. The little I read then made me shudder at the existence of anti-matter in the wrong hands. I'm grateful it's very expensive to create, the effects could be devastating.
Also thank you for the post, Knowledge Expounded!
Lol, as someone even said in a video I watched, "prohibitively expensive!"