Quasi-Periodic Eruptions (QPEs) are high-amplitude bursts of X-ray radiation recurring every few hours and provide a new channel to study how massive black holes are activated in low-mass galaxies. Previously, only two such sources were known, classified as hosting an actively accreting black hole. I will present the detection of QPEs in two further galaxies, obtained with a blind and systematic search during the first year of operations of the eROSITA X-ray telescope (Arcodia et al., Nature 2021). The optical spectra of these galaxies show no signature of black hole activity, indicating that a pre-existing accretion flow typical of active nuclei is not required to trigger these events. I will give a state-of-the-art overview of QPEs' multi-wavelength observational properties and possible origin scenarios. What we currently suggest is that QPEs might be driven by the presence of one (or more) orbiting body (-ies) with stellar mass. This could make QPEs a viable idate for the electromagnetic counterparts of the so-called extreme mass-ratio inspirals, with considerable implications for the future of multi-messenger astrophysics and cosmology.