International audienceSabotage modal logic was proposed in 2003 as a format for analyzing games that modify graphs they are played on. We investigate some model-theoretic and proof-theoretic aspects of sabotage modal logic, which has come to be viewed as an early dynamic logic of graph change. Our first result is a characterization theorem for sabotage modal logic as a fragment of first-order logic which is invariant with respect to a natural notion of 'sabotage bisimulation'. Next, we offer a sound and complete tableau method and its associated labeled sequent calculus for analyzing reasoning in sabotage modal logic. Finally, we identify and briefly explore a number of open research problems concerning sabotage modal logic that illuminate ...