  We present a single candidate transit event around Proxima Centauri, found
during a blind transit search using a robotic 30\,cm telescope at Las Campanas
Observatory. The event lasted 1 hour, with an estimated depth of 5\,mmag, and
is inconsistent with the transit window predicted for the recently discovered
planet b. We modeled the lightcurve under the assumption that the event was
caused by a transiting exoplanet, and our model predicts the planet has a
radius $R \sim 1 R_{\oplus}$. We encourage continued monitoring of Proxima to
elucidate the origin of this event.
