Left: redshift evolution of absolute magnitudes of SLSNe and their host galaxies. The upper panel shows Mg of SLSNe (blue circles) compared with the host Mg (orange squares). SN 2017egm and its host NGC 3191 are highlighted. The lower panel shows the magnitude difference between the SLSNe and their host galaxies. Right: spaxel BPT diagram for NGC 3191. The dotted line illustrates the indicative separation (at z = 0) of AGN and star-forming galaxies (Kewley et al. 2013). The solid line expresses the ridge line of SDSS galaxies (Brinchmann et al. 2008). NGC 3191 and the SN locations are similar to the massive host of PTF 10uhf.