In 1945, a Japanese Balloon Bomb Killed Six Americans in Oregon (2019)

Japan launched about 10,000 of these. Some made it as far east as Michigan. It's such a comically bad idea, but when you're at war, you're at war.

I suppose the architects of this plan really more intended to terrorize than do any actual damage. Of course, it failed on both accounts. This was the single explosion to cause real damage, and the US propaganda machine never would have allowed terror to spread anyway.