The phrase "plays mischief with" can be substituted with various synonyms that convey a similar meaning. For instance, "disrupts" expresses the idea of disturbing the normal functioning or flow of something. Another option is "interferes with," which suggests meddling or intruding in a process or situation. Similarly, "tamper with" denotes the act of meddling or altering in a harmful manner. Additionally, "meddles with" connotes a sense of meddling in a intrusive or harmful way. Likewise, "upsets" suggests a disturbance that causes confusion or disorder. Ultimately, by using any of these synonyms one can effectively convey the idea of something causing disruption or disturbance.