  Exploration of the novel relationship between magnetic order and topological
semimetals has received enormous interest in a wide range of both fundamental
and applied research. Here we predict that soft ferromagnetic (FM) material
EuB6 can achieve multiple topological semimetal phases by simply tuning the
direction of the magnetic moment. Explicitly, EuB6 is a topological nodal-line
semimetal when the moment is aligned along the [001] direction, and it evolves
into a Weyl semimetal with three pairs of Weyl nodes by rotating the moment to
the [111] direction. Interestingly, we identify a novel semimetal phase
featuring the coexistence of a nodal line and Weyl nodes with the moment in the
[110] direction. Topological surface states and anomalous Hall conductivity,
which is sensitive to the magnetic order, have been computed and are expected
to be experimentally observable. Large-Chern-number quantum anomalous Hall
effect can be realized in its [111]-oriented quantum-well structure.
