Botox is often administered in extremely diluted form for a number of medical conditions and to reduce facial lines. It is one of the deadliest toxins known, causing a binding at the point where nerve endings join muscles. Several cases of poisoning have resulted from "knock-off" versions of Botox, which have been reported to be in circulation. These knock-offs have higher concentrations of the Botulinum toxin. Botox is classified under what category of toxins?