The Multi Object Spectroscopic Explorer (MUSE) has revolutionised dense field spectroscopy by providing spectra of every 0.2"x0.2" over a field of view of 1'x1'. Here I will quickly review a few very recent results from MUSE spanning from exo-planets to Ly-a emitters via globular clusters, showing the power of this instrument to obtain spectra of faint objects. I will then present the first results from MUSE-Faint, a 100hr survey with MUSE of ultra-faint dwarf galaxies within the Milky Way halo. These are the most dark matter dominated objects we know and I will report on how we can use the dynamics of their stellar content to place the best current constraints on MACHO dark matter and present preliminary work on constraining the dark matter profile in these systems and thence the nature of dark matter in these galaxies.