It is called dodder, a parasitic annual plant.
hortster

Wow, thanks, Hortster! This is truly a creepy weed. Should my friend pull up the plant and burn it? Or is there some type of control that you know of?

If that were mine and I bought it at a box store, I'd pull it up and burn or dispose of in a plastic bag in the garbage. You can't find a root source because there isn't one just a few days following germination.

I found dodder in established echinacea years back but a very new infestation and I was able to get rid of it by pulling every single bit of thread like vine and watching carefully, closely inspecting surrounding soil for germinating seed - even at that very young dodder age I found what I think would have become mature seed pods/capsules on that vine. It hasnt appeared again - but the plant in your picture looks well on its way to being fully involved.

Here is a link that might be useful: Dodder - UCDavis

Looks like there are lots of weeds in that bed...I'd not be so quick to blame the nursery. The seedling dodder plant may have originated a few feet away from its new host plant and simply "traveled" until it found that nice, sturdy support to grow on.

Bad news? I think I see flowers on that dodder. Flowers means seeds mean more dodder. Right, morZ8?

Right. Flowers on weeds are never welcome, I find this one especially creepy for some reason. Must be the parasitic nature - really, plants without roots? While remotely interesting, there's just some yuck factor going on there...