Suppose you have two light waves which are coincident and inverted.
They would cancel each other.
If energy waves are random some waves are adding while others are subtracting.

But suppose a majority of waves were created in a single event, like the “big bang” and energy waves were created in a way that they tended to be opposites.

If two incident waves which are canceling eventually separate, would they appear to be created out of nothing?

Would they still exhibit mass according to the equation M = E/C^2 while they air cloaked?

If they did then space itself would exhibit a background invisible mass.

This mass may not be detectible in most conditions due to an density distribution which is close to a constant.