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1ES 1927+654 is a nearby active galactic nucleus (AGN) which underwent achanging-look event in early 2018, developing prominent broad Balmer lineswhich were absent in previous observations. We have followed up this object inthe X-rays with an ongoing campaign that started in May 2018, and that includes265 NICER (for a total of 678ks) and 14 Swift/XRT (26ks) observations, as wellas three simultaneous XMM-Newton/NuSTAR (158/169 ks) exposures. In the X-rays,1ES 1927+654 shows a behaviour unlike any previously known AGN. The source isextremely variable both in spectral shape and flux, and does not show anycorrelation between X-ray and UV flux on timescales of hours or weeks/months.After the outburst the power-law component almost completely disappeared, andthe source showed an extremely soft continuum dominated by a blackbodycomponent. The temperature of the blackbody increases with the luminosity,going from $kT\sim 80$eV (for a 0.3--2keV luminosity of $L_{0.3-2}\sim10^{41.5}\rm\,erg\,s^{-1}$) to $\sim 200$eV (for $L_{0.3-2}\sim10^{44}\rm\,erg\,s^{-1}$). The spectra show evidence of ionized outflows, andof a prominent feature at $\sim 1$keV, which can be reproduced by a broademission line. The unique characteristics of 1ES 1927+654 in the X-ray bandsuggest that it belongs to a new type of changing-look AGN. Future X-raysurveys might detect several more objects with similar properties.

The 450 days X-ray monitoring of the changing-look AGN 1ES 1927+654