临头 is a literary verb-object compound meaning 'to befall' or 'to be imminent', usually referring to something unpleasant or dangerous. It is often found in set phrases like 大难临头 ('great disaster looms'). As a separable verb (v.o.), the verb 临 and noun 头 can be separated: e.g., 临不到我头上 ('doesn't fall on me'). In modern usage it is most often used as a fixed unit. The subject is typically the event itself, and the person affected is indicated by context or a preposition like 在 or 到.