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Changing-look active galactic nuclei (CL-AGN) have been observed to changeoptical spectral type. Mrk 1018 is unique: first classified as a type 1.9Seyfert galaxy, it transitioned to a type 1 before returning to its initialclassification after approximately 30 years. We present a high-cadencemonitoring programme that caught a major outburst in 2020. Due to sunblock,only the decline could be observed. We studied X-ray, UV, optical, and IRbefore and after the outburst to investigate the responses of the AGNstructures. We derived a u'-band light curve of the AGN contribution alone. Theflux increased by a factor of the order of 13. We confirmed this in otheroptical bands and determined the shape and speed of the decline in eachwaveband. The shapes of H beta and H alpha were analysed before and after theevent. Two XMM-Newton observations from before and after the outburst were alsoexploited. The outburst is asymmetric, with a swifter rise than decline. Thedecline is best fit by a linear function, ruling out a tidal disruption event.The optical spectrum shows no change approximately 8 months before and 17months after. The UV flux increased slightly after the outburst but the X-rayprimary flux is unchanged. However, the 6.4 keV Iron line has doubled instrength. IR data taken 13 days after the observed optical peak show anincreased emission level. Calculating the distance of the broad-line region andinner edge of the torus from the supermassive black hole can explain themulti-wavelength response to the outburst, in particular: i) the unchanged Hbeta and H alpha lines, ii) the unchanged primary X-ray spectral components,iii) the rapid and extended infrared response, as well as iv) the enhancedemission of the reflected 6.4 keV line. The outburst was due to a dramatic andshort-lasting change in the intrinsic accretion rate. We discuss differentmodels as potential causes.

Still alive and kicking: A significant outburst in changing-look AGN Mrk 1018