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Very massive stars in the final phases of their lives often showunpredictable outbursts that can mimic supernovae, so-called, "SN impostors",but the distinction is not always straigthforward. Here we present observationsof a luminous blue variable (LBV) in NGC 2770 in outburst over more than 20years that experienced a possible terminal explosion as type IIn SN in 2015,named SN 2015bh. This possible SN or "main event" was preceded by a precursorpeaking $\sim$ 40 days before maximum. The total energy release of the mainevent is $\sim$1.8$\times$10$^{49}$ erg, which can be modeled by a $<$ 0.5M$_\odot$ shell plunging into a dense CSM. All emission lines show a singlenarrow P-Cygni profile during the LBV phase and a double P-Cygni profile postmaximum suggesting an association of this second component with the possibleSN. Since 1994 the star has been redder than during a typical S-Dor likeoutburst. SN 2015bh lies within a spiral arm of NGC 2770 next to a number ofsmall star-forming regions with a metallicity of $\sim$ 0.5 solar and a stellarpopulation age of 7-10 Myr. SN 2015bh shares many similarities with SN 2009ip,which, together with other examples may form a new class of objects thatexhibit outbursts a few decades prior to "hyper-eruption" or finalcore-collapse. If the star survives this event it is undoubtedly altered, andwe suggest that these "zombie stars" may evolve from an LBV to a Wolf Rayetstar over a very short timescale of only a few years. The final fate of thesetypes of massive stars can only be determined with observations years after thepossible SN.

SN 2015bh: NGC 2770's 4th supernova or a luminous blue variable on its way to a Wolf-Rayet star?