  We present the first calculations of the heavy flavor diffusion coefficient
using lattice QCD with light dynamical quarks. For temperatures
$195\,\mathrm{MeV}<T<352\,\mathrm{MeV}$, the heavy quark spatial diffusion
coefficient is found to be significantly smaller than previous quenched lattice
QCD and recent phenomenological estimates. The result implies very fast
hydrodynamization of heavy quarks in the quark-gluon plasma created during
ultrarelativistic heavy-ion collision experiments.
