How do you say something like that?
“There’s a thing for which I don’t know what it is” “There’s a thing where I don’t know what it is” “There’s a thing that I don’t know what is”
or (the one which I hear people say a lot but sounds awkward:) “There’s a thing that/which I don’t know what it is”?
To be honest they all sound awkward to me to varying degrees
What dis? Da fuq?
If you don’t know, I sure as hell don’t.
There’s a thing I can’t identify.
There’s a thing I don’t know about.
There’s an unfamiliar thing.
All the formulations you wrote indeed sound either ungrammatical or unwieldy to me.
I don’t know what that thing is.
I don’t know what that thing is for.
I don’t know what that is.
Any of these work for what you are trying to say?
“There’s a thing I’m unfamiliar with”
