In 1968, Brus staged his performance Der helle Wahnsinn (Sheer Madness) in Aachen, during which he cut into his chest with a razor blade for the first time. The painted line on the body in his earlier performances became a cut into his flesh; paint was replaced by blood. The self-harm that he had repeatedly addressed in his numerous performance drawings was now actually carried out. In 1970, his most radical action to date took place at Aktionsraum 1 in Munich: Die Zerreißprobe (Breaking Test). He cut his thigh with a razor blade, urinated on the wound, stitched it up himself, slashed the back of his head, whipped himself, threw himself to the floor and eventually lay there, exhausted. He has explored the limits of the body; a further escalation seems no longer possible. With Die Zerreißprobe, Brus brings his performance period to a close, yet a body-oriented, self-aggressive motif finds its way into his drawings. The theme of injury becomes particularly striking in his drypoint etchings. Brus works on the metal plates with steel needles, pocket knives, scissors, wire brushes and drills, and literally attacks them. He refers to himself as a "copper murderer". Prints such as Aktion (Action) or Fünf Kratzspuren (Five Scratch Marks) reflect this aggression and physical exertion. The figures depicted are besieged, cut into, penetrated and threatened in their very existence by the clusters of lines.