Gravity Spiders

Engineered matter-forms that can either function individually or lock together to form larger "warhead" structures. One of a retro-pre-emptive class of wepons, the spiders are projected as far back in time as energies allow, measuring the average gravitational pull of the universe as they pass backwards through it, and then wait for changes to the gravity at odds with the logged readings. This Time Thickening alerts the spiders to converge upon the point of the new object's arrival and lock together in warhead form, theoretically destroying whatever they find there.