  In this contribution, we present the MOBSTER Collaboration, a large community
effort to leverage high-precision photometry from the Transiting Exoplanet
Survey Satellite (\textit{TESS}) in order to characterize the variability of
magnetic massive and intermediate-mass stars. These data can be used to probe
the varying column density of magnetospheric plasma along the line of sight for
OB stars, thus improving our understanding of the interaction between surface
magnetic fields and massive star winds. They can also be used to map out the
brightness inhomogeneities present on the surfaces of Ap/Bp stars, informing
present models of atomic diffusion in their atmospheres. Finally, we review our
current and ongoing studies, which lead to new insights on this topic.
