  We present novel lattice results for the form factors of the quenched
three-gluon vertex of QCD, in two special kinematic configurations that depend
on a single momentum scale. We consider three form factors, two associated with
a classical tensor structure and one without tree-level counterpart, exhibiting
markedly different infrared behaviors. Specifically, while the former display
the typical suppression driven by a negative logarithmic singularity at the
origin, the latter saturates at a small negative constant. These exceptional
features are analyzed within the Schwinger-Dyson framework, with the aid of
special relations obtained from the Slavnov-Taylor identities of the theory.
The emerging picture of the underlying dynamics is thoroughly corroborated by
the lattice results, both qualitatively as well as quantitatively.
