Carrie Coon and Namir Smallwood go to dark places in Tracy Letts’s taut Broadway thriller.

The slipperiness of ostensible skepticism into utter credulity is what makes Bug continue to resonate so powerfully today. This is not just a particularly lurid folie à deux involving a peculiar variety of Ekbom Syndrome. It speaks to a larger crisis that has only expanded since Letts wrote the play: a twisted culture of conspiracy, exemplified by phenomena like QAnon and Pizzagate, that attracts broken people into collective psychosis. That’s the genuine horror built into this play, and perhaps also its most soothing aspect. In Bug, at least, the contagion is contained.