If you've ever heard of fugu -- that fish so dangerous to eat that Japanese sushi chefs need special certification to prepare it -- then you know that some pufferfish use seriously deadly toxins to protect themselves from predators. But according to a new study, these fish might benefit from their species' predilection for poison long before they're mature enough to produce it for themselves. A nice coating of deadly toxins might be Mom's parting gift to her babies.