The classic example is Young’s Double Slit experiment. The conclusion is that a single photon can interfere with itself. However, the pattern on the screen is exactly consistent with the (single) photon acting like a wave: interfering with itself, being in many places, and all that. In the double slit experiment the photon self-interferes between two uncertain sources in space (which slit did the photon go through?). As an aside, the Franson experiment also shows that not only do things have multiple futures (Young: the photon will go through both slits), but also that things have multiple pasts (Franson: the photon you observe was emitted at several different times).