Sartre’s character Roquentin seeing his hand as a crab is analogous in some ways to Nietzsche dreaming a toad on his transparent hand. Examining both of these envisioned animals as metaphors reveals that each represents some sort of physical or psychological disease or pestilence, that each profoundly disturbs the status quo, and that each point in a different way toward suicide, but at the same time that each signifies or symbolizes a deepening of self-knowledge. Both Nietzsche and Roquentin rejected suicide, but for different reasons: the former because he wished to remain in control of his life by consciously accepting his fate, no matter how repulsive it might be; the latter because he was too apathetic and despondent to care whether he lived or died. The purpose of this article is to suggest why depressed, suicidal people might reject suicide.