Could you possibly be talking about the "void"?
If you mean void as in the feeling of being in a large or endless void after taking hallucinogenic drugs, it could be a little different. The kind of void I was talking about is more like feeling completely physically distant from everything, as if you are in a part of the universe which reflects no light or sound, you are in a tiny box and at the same time in a complete void which is paradoxically the same as the tiny blank box. Then the box is forcefully lifted... there is nothing there, just the essence of fear. It transforms into terrifying places and scenarios, the essence is an emotional being itself.
...?
Infinite fear comes with infinite discovery and realization... I'm talking about the first half.