There's a concept called The Great Filter. Soemthing that aims to explain why alien life hasn't contacted us yet.
It's basically saying, if life exists elsewhere, it has to pass a stage where they become interplanetary.
Humans may be first, known as being ahead of the great filter.
The other side is that we haven't hit the filter yet.
The filter could be anything. Home planets not having enough resource to kick start the next phase. Species too self destructive to focus on current goals. Disease/natural disasters keep things in check, etc.
To get back on point. Some people like to imagine the filter is indeed what you say. Something watching, waiting, that we can't see, that waits for lifeforms to reach a certain phase in space and then just go nom.
We could easily be fish jumping out a river to some higher level being and we're just their dinner.
Death could be what's eating us. It claims us all.