dangerous instrumentality. An instrument, substance, or condition so inherently dangerous that it may cause serious bodily injury or death without human use or interference. • It may serve as the basis for strict liability. See ATTRACTIVE-NUISANCE DOCTRINE. Cf. deadly weapon under WEAPON. [Cases: Negligence 305–307, 1172–1178. C.J.S. Negligence §§ 170, 176–179, 399, 476–477, 494–526.]