From the time it was completed nearly four hundred years ago, Caravaggio’s painting of a nude boy embracing a ram (today in the Pinacoteca Capitolina, Rome) has confounded viewers as to its subject, which has been variously called ‘Pastor friso’, Saint John the Baptist, Corydon, Paris, and ‘nude youth with a ram’. This essay argues that none of these titles accounts for what we see in the painting and, no less importantly, what we do not. Using a range of modes of analysis, we propose a new reading of the painting as a variant on the theme of the Sacrifice of Isaac, one that has fascinating implications for Caravaggio’s conception of the viewer–subject relationship and which contributes to a deepening of our understanding of one of early modern Europe’s most innovative and provocative painters.