The phrase "intrude upon" can be replaced by a number of synonyms that convey a similar idea. Some possible options include "invade," "encroach," "trespass," "impinge," "violate," and "disrupt." These terms each imply that someone or something is disrupting a space or situation, often without being invited or welcomed. "Invade" suggests a forceful, aggressive intrusion, while "trespass" evokes the idea of crossing a physical or social boundary. "Impinge" conveys a sense of encroachment that may not be intentional, while "violate" suggests a more deliberate or nefarious act. "Disrupt" is a more general term that can apply to any kind of unwanted interference or interruption.