Dark DAOs allow for undetectable private coordination and are feasible to launch in Ethereum today. In this talk, I will introduce Dark DAOs, highlight applications that should be aware of their possibility, and point to the ways they can be harnessed as mechanisms for both prosocial and antisocial coordination. I will also discuss how the encumbrance of keys utilized by Dark DAOs can generalize. I will introduce Proofs of Complete Knowledge as an available countermeasure.