  Magnetometry and magnetoresistance (MR) data taken on the van der Waals
ferromagnet Fe$_{3-x}$GeTe$_2$ (FGT) reveal three distinct contributions to the
MR: a linear negative component, a contribution from closed Fermi-surface
orbits, and a $H^2$ enhancement linked to a non-coplanar spin arrangement.
Contrary to earlier studies on FGT, by accounting for the field dependence of
the anomalous Hall effect, we find that the ordinary Hall coefficient decreases
markedly below 80 K, indicating a significant change in character of the
electrons and holes on the Fermi surface at this temperature. The resulting
altered ground state eventually causes the Hall coefficient to reverse sign at
35 K. Our Hall data support the proposal that Kondo-lattice behavior develops
in this $d$-electron material below 80 K. Additional evidence comes from the
negative linear component of the MR, which arises from electron-magnon
scattering with an atypical temperature dependence attributable to the onset of
Kondo screening.
