  The charge dynamics of Ba(Fe$_{1-x}$TM$_x$)$_2$As$_2$ (TM = Mn and Cr) has
been investigated by optical spectroscopy. It was found that in addition to the
strong suppression of the coherent charge transport, the magnetic impurity
induces a novel spectral feature related to the carrier localization in the
far-infrared region above the antiferromagnetic transition temperature. We
attribute it to the cooperative effect between conduction electrons and local
magnetic order induced by magnetic impurities. The present results demonstrate
that Mn and Cr are not conventional magnetic pair-breakers in iron pnictides.
