Idk...

I personally think it looks more like a humanoid face than what the Basilisk looked like. Interesting theory tho... :D

@Dialby31

@Stormshock the animus ElectricWing

@WeLoveHedwig

It’s meant to be Voldemort’s face because his Horcrux was destroyed. You can even see it in the fire in the Room of Requirement when the Diadem is destroyed and even the black smoke when Neville kills Nagini.