The puffer fish, also called blowfish, swellfish, globefish, balloonfish, bubblefish are fish making up the family Tetraodontidae, within the order Tetraodontiformes. They are named for their ability to inflate themselves to several times their normal size by swallowing water or air when threatened; the same adaptation is found in the closely related porcupinefish, which have large conspicuous spines (unlike the small, almost sandpaper-like spines of puffer fish). The scientific name, Tetraodon, refers to the fact that they have four large teeth, fused into an upper and lower plate, which are used for crushing the shells of crustaceans and mollusks, their natural prey. The eyes and internal organs of most puffer fish are highly toxic, but nevertheless the meat is considered a delicacy in Japan and Korea. Tetrodotoxin, a chemical present in the pufferfish, is a powerful neurotoxin that can cause death in nearly 60% of the humans that ingest it. A human only has to ingest a few milligrams for a fatal reaction to the toxin to occur.