supply in early times and are now extremely dark matter dominated, allowing them to survive in such dense environments [@vandokkum2015a]. Two objects in Coma, Dragonfly 17 and Dragonfly 44, and one in Virgo, VCC 1287, are possible examples of such a scenario. Dragonfly 17 hosts ${\sim}30$ globular clusters (GCs), abnormally high for its luminosity, suggesting it could possibly be a “failed" M33- or LMC-like galaxy [@peng2016; @beasley2016b]. VCC 1287 is similarly a possibly failed LMC-like galaxy based on its GC system [@beasley2016a]. Dragonfly 44 is much more massive, with ${\sim}75$ GCs and a dynamical mass consistent with being a failed Milky Way-like system [@vandokkum2016; @vandokkum2019b]. Subsequent investigations, however, suggest that many UDGs have stellar masses and dark matter halos consistent with dwarf galaxies suggesting Dragonfly 44 may be an extreme case [@beasley2016a; @peng2016; @amorisco2018; @alabi2018; @ferre-mateu2018]. At the other extreme, two UDGs in the NGC 1052 group, NGC1052-DF2 and NGC1052-DF4, have very low velocity dispersions and dynamical masses consistent with little or no dark matter [@vandokkum2018a; @vandokkum2019a; @danieli2019a].

With such a range of properties exhibited by UDGs, the low surface brightness universe is proving to be just as diverse as the high surface brightness universe. Numerous formation channels have been 