Guanitoxin
Guanitoxin (GNT), formerly known as anatoxin-a(S) "Salivary", is a naturally occurring cyanotoxin commonly isolated from cyanobacteria (specifically of the genus Anabaena). It is a potent covalent acetylcholinesterase inhibitor, and thus a potent rapid acting neurotoxin which in cases of severe exposure can lead to death.