So, I don't aggree with the quote below, that a basilisk and cockatrice are the same thing. My first exposure to cockatrices was in a story called Stone, by Peter Dickinson. Basilisks and cockatrices were described as seperate creatures (and even if this specified nomenclature is linguistically recent) so that's the way I'll always think of them.
'Once in a great while, when the positions of the stars are just right, a seven-year-old rooster will lay an egg. Then, along will come a snake, to coil around the egg, or a toad, to squat upon the egg, keeping it warm and helping it to hatch. When it hatches, out comes a creature called basilisk, or cockatrice, the most deadly of all creatures. A single glance from its yellow, piercing toad's eyes will kill both man and beast. Its power of destruction is said to be so great that sometimes simply to hear its hiss can prove fatal. Its breath is so venomous that it causes all vegetation to wither.
'There is, however, one creature which can withstand the basilisk's deadly gaze, and this is the weasel. No one knows why this is so, but although the fierce weasel can slay the basilisk, it will itself be killed in the struggle. Perhaps the weasel knows the basilisk's fatal weakness: if it ever sees its own reflection in a mirror it will perish instantly. But even a dead basilisk is dangerous, for it is said that merely touching its lifeless body can cause a person to sicken and die.'