coincidence, (or if said under one's breath)... a Suspiciously Unusual Coincidence.
Street slang by barely literate Irish, Jewish, German, Italian and Chinese street toughs (such as the Pug Uglies , Black Hand, Purple Gang and Tong Hatchet Men) from NY's ethnic ghettos of the 19th Century, specifically, the Lower East Side, Five Points, China Town (Manhattan), and Flatbush, Empire, Coney Island (Brooklyn)... later evolved into nationally used street slang by early 30s talkie gangster /prison movies and then into the common vernacular by such comedians as The Three Stooges' and 'The Marx Brothers'.
a non-fancy way of talking about Carl Jung's idea of synchronicity:
Synchronicity is an explanatory principle; it explains "meaningful coincidences." His notion of synchronicity is that there is an acausal principle that links events having a similar meaning by their coincidence in time rather than sequentially. He claimed that there is a synchrony between the mind and the phenomenal world of perception.
A beetle flew into Jung's room while a patient was describing a dream about a scarab. The scarab is an Egyptian symbol of rebirth, he noted. Therefore, the propitious moment of the flying beetle indicated that the transcendental meaning of both the scarab in the dream and the insect in the room was that the patient needed to be liberated from her excessive rationalism.