This is driving me crazy. I vaguely remember buying a powdered alcohol (not THAT powdered alcohol) online. You would mix it with water, and it would have peculiar properties. I THINK it became a very viscous liquid that would break if you pulled it quickly, but flow if you poured it. It seemed to have some characteristics in common with silly putty, but was definitely clear and mainly liquid. Does this ring a bell with anyone.
http://www.west.net/~science/slime.htm 
“solution of Polyvinyl Alcohol (PVA) and a solution of Sodium Metaborate (Borax) are mixed together.”
"The cross linking is weak, so the links continually form and break under the weight of the gel, or with handling. Leave a ball of the slime on a flat surface, and it slowly flattens out as the molecular chains slide over each other, rearrange themselves and reconnect. But if you pull suddenly on the material, it snaps. "
My brother is a statistician with a chemistry degree (long story). The last time I visited him he took some powder and mixed it with water, forming a gel with strange properties (we were all high).
IIRC he said the powder was similar to whatever makes disposable diapers work.
Polyvinyl Alcohol isn’t a powder, though, as the OP requires. In fact, although technically a polymer, the supposed monomer “vinyl alcohol” doesn’t really exist.
Adding the borax causes (weak, as you note) cross-linking to occur, making the liquid PVA into more of a viscous “slime”. It’s better if you add green coloring to the normally colorless PVA, because then you get wonderful Green Slime. I’ve done this experiment with kids.
The problem is, you have to order the PVA from someplace like Steve Spangler Science, because it’s not exactly a household item.
It’s easier to get hold of white glue (like "Elmer’s glue) and dilute it somewhat. It’s Polyvinyl Acetate, first cousin to Polyvinyl Alcohol (with the same initials). Adding borax solution will cause it to cross-link in the same way. But it looks an opaque to translucent white, instead of a clear liquid.
Thank you so much. My kind can now be quiet.
There are other powders that will absorb a lot of water, resulting in a viscous liquid that will “break” if pulled rapidly. Polyoxyethylene, AKA “Polyox”, or Polyethylene glycol is one of these. It’s a white powder (but not an alcohol), and you have to be careful in how you mix it with water, or it’ll clump. But it turns clear viscous stream. If you add more water to it, it’ll get thinner, but remain a viscous stream.