  The electrical Hall effect can be significantly enhanced through the
interplay of the conduction electrons with magnetism, which is known as the
anomalous Hall effect (AHE). Whereas the mechanism related to band topology has
been intensively studied towards energy efficient electronics, those related to
electron scattering have received limited attention. Here we report the
observation of giant AHE of electron-scattering origin in a chiral magnet MnGe
thin film. The Hall conductivity and Hall angle respectively reach 40,000
{\Omega}-1cm-1 and 18 % in the ferromagnetic region, exceeding the conventional
limits of AHE of intrinsic and extrinsic origins, respectively. A possible
origin of the large AHE is attributed to a new type of skew-scattering via
thermally-excited spin-clusters with scalar spin chirality, which is
corroborated by the temperature-magnetic-field profile of the AHE being
sensitive to the film-thickness or magneto-crystalline anisotropy. Our results
may open up a new platform to explore giant AHE responses in various systems,
including frustrated magnets and thin-film heterostructures.
