"Do you know how incredibly unnerving it is to have your hand refuse to do what it's told, and then go off in a completely different direction?"
Does more than write? What's it writing? What liquid does it write in? How old is it? Bonds with paper? It's trying to send a message to someone/thing?
Ancient, dusty stone shield w/ Foundation symbol?
Pure of Justice? Column inscribed in Akkadian cuneiform interspersed with unknown stretches of symbols, seems to be extended Code of Hammurabi, judges all within (Radius of Babylon at the time of Hammurabi) -Needs more mystery, and some sense of dread.
-Maybe takes something of the person, depending on how severe? Organs, senses, skills and capacities (Capacity to learn, sense of direction, memory- Maybe get these from esoteric ailments)
-Foundation has been maliciously cursed with this item, knowing they will not relinquish it, but that it will cause much -(Harm/Revenge?)-"Here's a Foundation for *you*. See ya, suckers!"-Found by agent, goes rogue, leave hints that he's corrupted by the removal of something in his brain, overarching plan by GOI?
-Unpredictable surges make containment difficult
Bronze statue, moves extremely slowly, measured in months, but is absolutely unstoppable.
All of these need to have some semi-concrete origin story, even if it's unsaid. Can't just have appeared out of nowhere.
Alien Refuse capsule- Shot at altered trajectory (leading from a black hole?) to keep selves secret, imply they're trying to go unnoticed. Filled with super-powerful energy containers (equate to fuel rods) -With all their power, they're trying to stay hidden from something bigger, ultra-heavy security/secrecy.
-TALE: Agent assigned to clean up after/second-guess D-Class. MTF First in, Last out.
-TALE: Agent assigned to vette the huge number of false positives.