It was actually Roundup - got it at Home Depot. It just didn't work. Even after a week or more. I didn't really expect the grass to be dead and gone in 6 hours. I just thought the whole "results within 6 hours" claim was a little bit misleading when all it did was turn some of it brown and leave the rest unaffected (seemingly).

I gave in and just dug up the grass in the area (luckily it was small, otherwise I could have had a good workout).

Who knows - maybe I got part of a "weak batch" or something.