Fugu, a.k.a. blowfish, a.k.a. puffer fish, a.k.a. the-fish-that-can-kill, is known for containing a deadly neurotoxin. It’s found in the Pacific and the Atlantic. The meat is a delicacy in Japan, where only qualified masters deal with it.
Yamada3 says there’s a non-poisonus variety called kawa-fugu that comes from the Boston area. It doesn’t taste as good, though.
In some parts of the U.S. it’s not legal to prepare fugu, so much of what we have arrives pre-cut. Masa, in New York City, is licensed and is probably the best bet for getting the real deal, according to K K.