Infrared observations taken during the major outburst seen in 1993 sho
w strong evidence of rapid variability in 3C 66A on a time scale of a
few hours, with associated variability of the spectral slope on the sa
me time scale. A strong (P much greater than 99%) correlation is seen
between the flux at 2.2 microns and the spectral index, with the spect
rum steepening as the flux rises, the opposite trend to that seen norm
ally in blazars. Such rapid variability cannot easily be explained by
current relativistic jet models; a better option is black body radiati
on from hot spots on the accretion disk, possibly linked to strong mag
netic fields, although the rapid time scale of the variation and its e
nergetics pose serious problems. One possible solution is to invoke br
emsstrahlung radiation from a flare, which is later modified by a high
degree of extinction through the disk.