Several people have died in Russia after anglers decided to make a tasty fish soup using fugu fish.
The fugu is not usually found off Vladivistock, where the incidents have taken place, but their numbers have grown over the warm summer weather.
The pufferfish is known as fugu in Japan, where chefs have to have a special license to prepare it.
There is enough poison in a single puffer fish to kill 30 people. Parts of the fish contain a toxin called tetradotoxin which can be up to 1200 times more poisonous than cyanide.
Symptoms of tetradotoxin poisoning can occur anything from 15 minutes to several hours later and include numbness, nausea, vomiting, extreme stomach pains and sometimes paralysis and death.
There is no known antidote to tetradotoxin poisoning.