  We present the gamma-ray, X-ray, optical and radio data for GRB100814A. At
the end of the slow decline phase of the X-ray and optical afterglow, a sudden
and prominent rebrightening in the optical band occurs followed by a fast decay
in both bands. This optical rebrightening is accompanied by possible chromatic
variations. We discuss possible interpretations, such as double component
scenarios and internal dissipation mechanism, with their virtues and drawbacks.
We also compare GRB100814A with other Swift bursts that show optical
rebrightenings with similar properties.
