A black flag with a skull and crossbones and the slogan in Ukrainian, "Death to all who stand in the way of freedom for the working people." 
It was widely believed to be one of the main flags of Nestor Makhno's Revolutionary Insurgent Army of Ukraine, since it was first labelled a "Makhnovist banner" in the 1926 book "Jewish Pogroms: 1918–1921" by Z.S. Ostrovsky (under Section VIII, "Pogromists.")

In 1927, Makhno himself published an article in Delo Truda, denying allegations that his forces committed pogroms, and asserted that the skull and bones flag had no connection to his army. The flag is believed to have belonged to the forces of the Ukrainian insurgent Svyryd Kotsur.
Own work
Hoodinski