I have in mind a metallic chain, something like a watch strap. The links are shaped to obstruct motion, so that the chain cannot flex towards one direction, and maybe 45° per link in the other direction. Each link has a magnet, and the magnets are such that, when one link is stuck to a magnetic surface, the magnets pull subsequent links until the entire chain ends up stuck to the surface. This clip from the old Spider-Man 2 movie (Doctor Octopus) is something like what I mean: Birth of Doctor Octopus - YouTube
Is there any thing that does this? Or am I remembering some magic bracelet from a movie?