"The derivation of the name Basil is uncertain. Some authorities say it comes from the Greek basileus, a king, because, as Parkinson says, 'the smell thereof is so excellent that it is fit for a king's house,' or it may have been termed royal, because it was used in some regal unguent or medicine. One rather unlikely theory is that it is shortened from basilisk, a fabulous creature that could kill with a look. This theory may be based on a strange old superstition that connected the plant with scorpions. Parkinson tells us that "being gently handled it gave a pleasant smell, but being hardly wrung and bruised would breed scorpions. It is also observed that scorpions doe much rest and abide under these pots and vessells wherein Basil is planted." It was generally believed that if a sprig of Basil were left under a pot it would in time turn to a scorpion. Superstition went so far as to affirm that even smelling the plant might bring a scorpion into the brain.
Culpepper says:
'Being applied to the place bitten by venomous beasts, or stung by a wasp or hornet, it speedily draws the poison to it. -Every like draws its like. Mizaldus affirms, that being laid to rot in horse-dung, it will breed venomous beasts. Hilarius, a French physician, affirms upon his own knowledge, that an acquaintance of his, by common smelling to it, had a scorpion breed in his brain.'"
-Grieve, M. A Modern Herbal; The Medicinal, Culinary, Cosmetic and Economic Properties, Cultivation and Folk-Lore of Herbs, Grasses, Fungi, Shrubs, & Trees with All Their Modern Scientific Uses. London: Tiger Books International, 1992.