Nonliving monsters are inanimate objects and substances which have gained autonomy via magical, technological, or natural means. (Undead monsters, by contrast, were at one time alive.)
All nonliving monsters are immune to negative energy, confusion, and asphyxiation (being unbreathing). They can be slowed (unless they are immobile), but not put to sleep. Most – but not all – nonliving monsters are also resistant to poison and electricity. The training dummy, for instance, is resistant to neither.