Non-canonical objects in Mandarin Chinese denote instrument, time, manner, and so on, instead of theme. The predicates that contain such objects show properties of unergative predicates. The paper thus claims that the syntactic position of such objects is the complement of a verb in the unergative use. The semantic function of such objects parallels that of classificatory adjectives in the nominal domain, and that of pseudo-incorporated nominals in the verbal domain. Such objects denote properties, and restrict, rather than saturate, predicates. Non-canonical objects are thus identified as event kind-classifying elements. Four properties of such objects motivate this analysis. They are never in the form of a pronoun, and never admit comparison; their hosting predicate encodes a subclass of an event kind, and the event is subject to an institutionalization constraint. Such objects are thus not arguments or adverbials. The paper further claims that since these properties are also found in cognate objects and weak definites in English, these two types of nominals are also event kind-classifying elements. These different types of nominal event kind-classifying elements are all complements of their associated verbs.