Multi-color evolution of KSP-OT-201509a. Blue, green, and red points represent measurements in B, V, and I respectively. The dashed lines show the best-fit power-law decay trends (﹩{F}_{{\rm{v}}}\propto {t}^{-\alpha }﹩). The inlet figure shows the rising phase in more detail. The vertical line at UT 270.67 indicates the approximate onset of the pre-maximum halt.