Castor beans contain ricin, which is a lethal poison. It just takes a single grain of sand to destroy someone. The toxin acts by inactivating ribosomes and stopping protein formation, which is a deadly issue. The poison has no solution, but it is possible to survive if the dosage is minimal enough. In 1978, Georgi Markov was assassinated with ricin. ¹⁾

Tetradotoxin or TTX is a potent neurotoxin that blocks sodium channels from shutting down the nerve passage between the brain and the body. A small dosage will induce weakness and lack of feeling, but just a little bit more paralyzes muscles that you use to survive. It takes about 5 hours for the full effect to take effect, but if the diaphragm ceases functioning, the lungs can no longer inhale or exhale, and you're dead. Alternatively, an erratic pulse may cause you to die faster. ²⁾