Army tent pills.
The United States Army once developed these tents that were so small they could be carried around in a pill. When soldiers were on the field and they needed shelter, they could just add water to the pill and it would turn into a tent. They had to stop making them, though, because sometimes soldiers would think they were aspirin and eat them. The pills would turn into tents inside of their stomachs and make them die a horrible death. The Pentagon kept it top secret because they didn't want people to know so many people died from eating tent pills. My uncle has one of the last remaing tent pills, but he keeps it locked up in a jar so nobody accidentally eats it.