  We find that a heavy gluon G of mass 800-900 GeV with small, mostly
axial-vector couplings to the light quarks and relatively large vector and
axial-vector couplings to the top quark can explain the t \bar{t}
forward-backward asymmetry observed at the Tevatron with no conflict with other
top-quark or dijet data. The key ingredient is a complete treatment of
energy-dependent width effects and a new decay mode G->qQ, where q is a
standard quark and Q a vector-like quark of mass 400--600 GeV. We show that
this new decay channel makes the heavy gluon invisible in the t\bar{t} mass
invariant distribution and discuss its implications at the Tevatron and the
LHC.
