There's more than one way to skin a cat - use a robot rather than a material. Check out this description of tensile memory polarized matter in the 1966 short novel Babel 17 by Samuel R. Delany:
He raised his hand. "Suppose you needed a gun"—in the Barons's hand now was a sleek vibra-gun of a model later than she had ever seen — ''or a crescent wrench." Now he held a foot long wrench. He adjusted the opening. "Or a machete." The blade glistened as he waved his arm back...
An unexpected property of polarized matter is tensile-memory." They moved toward an archway Into the next room. "Annealed in any shape for a time, and codified, the structure of that shape is retained down to the molecules. At any angle to the direction that the matter has been polarized in, each molecule has completely free movement. Just jar it, and it falls into that structure like a rubber figure returning to shape." The Baron glanced back at the case.
"Simple, really. There"—he motioned toward the filing cabinets along the wall—"is the real weapon: approximately three thousand individual plans incorporating that little polarized chunk..."
(Read more about Tensile Memory Polarized Matter)
A more modern version of this idea can be found in the 2007 Transformers movie; a robot that can disguise itself as a variety of ordinary electronic tools.
The Number 2 vignette in the video, a "smart wristband" that can give alerts, actually tapping your wrist, reminded me of Frakir from Trumps of Doom, one of the second Amber series of fantasy novels by Roger Zelazny:
Frakir was a magical entity, not a robot, but took the appearance of a piece of rope that could coil around the wrist of its owner, and provide warnings - as well as other functions:
Frakir cut into my wrist. I sought about quickly after any approaching menaces, but I saw nothing. I remained wary for several minutes longer, exploring the vicinity. Nothing occurred, though, and Frakir grew still.
It was hardly the first time her alarm system had been improperly cued — whether by some stray astral current or some odd thought of my own. But in a place like this, one could not afford to take chances. The highest stand of stone in the vicinity stood at about fifteen to twenty meters, perhaps a hundred paces uphill, to my left. I made my way over to it and commenced climbing.
When I finally reached its chalky peak, I commanded a view over a great distance in every direction. I did not behold another living thing in this strange silent yin-yang universe.
So I decided that it had indeed been a false alarm, and I climbed back down. I reached once again to summon the Logrus and Frakir practically behanded me. Hell. I ignored her, and I sent out my call.
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