In 2005, there was a pond near Hamburg, Germany, where about a thousand toads exploded in just a few days. The event dumbfounded scientists for several weeks. The area was closed down by the police out of fear of a infectious disease.
Finally, an animal doctor found the explanation: The toads were so distracted due to their mating season that crows, which also lived near the pond, could pick the toads' skin open, pull out their liver and eat it. Later, when the toads tried to inflate their bodies as a defensive reaction, the opened skin couldn't hold the pressure, leading to the explosion.