The story of the astrologer Ascletario is introduced by Suetonius as the last item in a series of portents and predictions presaging Domitian’s violent death. This paper gives an analysis of this episode, discussed in the wider context of the catalogue of portents in Dom. 15.2-3 and, indeed, of the whole death narrative of the biography. A comparison to the parallel story in Cassius Dio (67.16.3) reveals important differences between the two authors; it is argued that Suetonius is closer to the original version of the anecdote and that Dio may have been influenced by Herodotus’ story of Croesus on the pyre. It is also argued that Suetonius expects his readers to connect the Ascletario episode with another Flavian portent, reported at Ves. 7.4 (dogs are prominent in both). Two other ‘canine’ passages of the Domitian, 10.1 and 23.1, are briefly discussed. The proposed analysis supports the view of Suetonius as an author who carefully structured his biographical rubrics and invited his readers to make connections within both a single biography and wider textual units.