What if the Basilisk wasn’t meant to harm the students? What if Salazar had intended for it to be a last line of defense should the school be attacked?
All of the Founders had agreed that the school needed protecting. Magic was feared and terrible violence was brought on those thought to posses it. Knowing the students were their first priority and their safety was of the utmost importance, they set out to each add a layer of protection to the school. Rowena created a powerful barrier spell that would be taught to all the future teachers. Godric crafted great stone knights to be enchanted and brought to life. Helga rounded up an army of House Elves to serve the school in times of peace as well as defend in it’s hour of need.
Salazar, wishing to out-do them all first suggested keeping cauldrons of rather nasty potions kept along the ramparts of the castle. But his idea was disregarded by the others, concerned that students might come in contact with the vats accidentally. And so he turned to his second greatest talent, Parseltongue. But no ordinary snake would do. So he hatched a Basilisk, though wishing to shock and awe his fellow founders, he told them nothing of his plans. Wishing for the creature to know no other home but Hogwarts he reared it in secret within the deepest dungeons. However, a Gryffindor student noticed his comings and goings and much like Harry’s constant suspicions of Snape centuries later, decided to follow him.