A planet and a moon orbiting around their barycenter will reach that point (the barycenter) faster than expected when the moon transits the planet, because of how the barycenter functions. Objects of certain sizes and masses outside of half the distance of Earth and the Sun, and anything between 0.1 and 10 Jupiter masses, are unusual. The dip seen in the Kepler data stemmed from a Neptune-sized moon around a Jupiter-sized planet.