In European bestiaries and legends, a basilisk is a reptile reputed to be king of serpents and is said to have the power to cause death with a single glance. According to some accounts, the breath of a basilisk is so toxic that it can kill a fully-grown adult in seconds.
The basilisk is called “king” because it is reputed to have a crown-shaped crest on its head . The basilisk is alleged to be hatched by a cockerel from the egg of a serpent or toad. In Medieval European legends, the description of the creature began taking on features from cockerels.
Although there is some anecdotal evidence to indicate that basilisks exist, no conclusive proof has ever been produced.