Okay, to fully get this one you need knowledge of:

• Japanese cuisine. Fugu is a genus of puffer fish, regarded by many Japanese as a delicacy. Unfortunately, its liver and other organs contain lethal concentrations of the highly toxic tetrodotoxin. This is normally removed by the specially trained and licensed chefs who are the only ones allowed to prepare the fish for consumption. But sometimes mistakes are made, and some poison remains in the prepared dish. Diners eating it feel a tingling sensation, followed by paralysis, and death. There is no cure, and a few people die this way in Japan each year.
• French language. Poisson is French for "fish".
• Statistics. The Poisson distribution is a statistical distribution first described by Siméon-Denis Poisson, a French mathematician who lived from 1781 to 1840. The distribution describes the expected number of events of a fixed probability occurring within a fixed interval of time - such as the expected number of deaths due to fugu poisoning in Japan in a year.