Horror beyond human comprehension

I was talking to a friend about this and I wanna know what is everyone's take on the "horrors beyond my comprehension" type of horror.
A common sentiment online is describing it as "understanding something impossible for a split second".

Personally I like more the "understanding something you never have any way of explaining to anyone else". Like, you finally get it, it all makes sense. There is no words in any human language that could possibly express what you have found out.