Mexican Jumping Beans (70s)
Native to Mexico, the seeds are inhabited by the larva of a small moth. When the beans are heated, the beans jump because the larva are experiencing spasms. The spasms are the larva trying to roll the seed to a cooler environment in order to avoid dehydrating and/or dying. These beans are not toxic, but they aren’t meant to be eaten.
It doesn’t take much heat to get the beans to “perform,” simply holding them in your palm can do the trick. Prolonged exposure to heat (like direct sunlight) for a few hours will kill the larvae.
You can still purchase Mexican Jumping Beans. They’re widely available online or check your local joke shop.