We have found a novel intracluster reaction proceeding in large ammonia or ammonia/argon clusters upon excitation with ArF excimer laser radiation which leads to the formation of unprotonated and prototaned hydrazine clusters, (N2H4)(n)(+) and (N2H4H+ (n=1-4). To our knowledge it is the first time that the production of bare clusters of a different chemical species has been observed as a result of an intracluster reaction. Besides neat hydrazine complexes also mixed cluster ions containing hydrazine and ammonia molecules were detected, both as unprotonated and protonated species. However, the bare hydrazine clusters were found to be more abundant. It is assumed that the wavelength of the exciting laser radiation is of great importance for inducing the observed reaction.