Basilisk (folklore)

A Basilisk is a legendary lizard closely related to the Cockatrice and believed to be inspired by varied snake species found in the world - it was considered a "king" of lizards and had the frightening ability to kill with a single glance.

The Basilisk is also said to be so incredibly poisonous that it leaves behind a burning trail of posion everywhere it goes and indeed this is how one could identity a Basilisk's hole - due to the ground being scorched around it.

The only way folklore said a Basilisk could be harmed or driven away was via the odour of a weasel, presumably due to the fact weasels are natural predators of lizards and snakes (especially the mongoose).