  We present evidence of wavelength-dependent variations within the infrared,
optical, and ultraviolet pulse profile peaks of the Crab Nebula pulsar. The
leading and trailing edge half-width half-maxima of the peaks display clear
differences in their wavelength dependences. In addition, phase-resolved
infrared-to-ultraviolet color spectra show significant variations from the
leading to trailing edges of the peaks. The color variations between the
leading and trailing edges remain significant over phase differences smaller
than 0.0054, corresponding to timescales of $<180 \mu$s. These results are not
predicted by any current models of the pulsar emission mechanism and offer new
challenges for the development of such models.
