Answer:
It is a sound of empty, speak and it'll talk back plenty. But all the more you yack, you'll get the same words back.
Always wax, yet always wane: I melt, succumbed to the flame. Lighting darkness, with fate unblest, I soon devolve to shapeless mess.
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
What goes in the water black and comes out red?
By the way, what never moves, wears shoes, sandals and boots, but has no feet?
I will disappear every time you say my name.