We report the discovery of weak yet hard X-ray emission from the Wolf-Rayet ( WR ) star WR 142 with the XMM-Newton  X-ray telescope . Being of spectral subtype WO2 , WR 142 is a massive star in a very advanced evolutionary stage , short before its explosion as a supernova or \gamma -ray burst . This is the first detection of X-ray emission from a WO-type star . We rule out any serendipitous X-ray sources within \approx 1 ^ { \prime \prime } of WR 142 . WR 142 has an X-ray luminosity of L _ { X } = 7 \times 10 ^ { 30 } erg s ^ { -1 } , which constitutes only \raisebox { -1.72 pt } { $ \stackrel { < } { \scriptstyle \sim } $ } 10 ^ { -8 } of its bolometric luminosity . The hard X-ray spectrum suggests a plasma temperature of about 100 MK . Commonly , X-ray emission from stellar winds is attributed to embedded shocks due to the intrinsic instability of the radiation driving . From qualitative considerations we conclude that this mechanism can not account for the hardness of the observed radiation . There are no hints for a binary companion . Therefore the only remaining , albeit speculative explanation must refer to magnetic activity . Possibly related , WR 142 seems to rotate extremely fast , as indicated by the unusually round profiles of its optical emission lines . Our detection implies that the wind of WR 142 must be relatively transparent to X-rays , which can be due to strong wind ionization , wind clumping , or non-spherical geometry from rapid rotation .