I'm not too sure if it does exist as I haven't come across it yet.

I think it all depends on the person as well. You get a smoker who's been puffing for 2months, get their hands on some really great weed, claim it's one hit shit, but then you get a smoker who's been smoking for 2yrs, smokes the same stuff, but is NO one hit shit.

I've had stuff that was like a 2 hit shit. Then again that was when I was new to smoking, so, I don't know, I'm rambling.