Hippolyte Terentyev is the young consumptive of The Idiot, seventeen or eighteen years old, with only a few weeks to live, who reads to the prince's guests the Explanation, the text in which he decides to kill himself at sunrise, and whose pistol, without a cap, does not fire.
He appears in Part Two, in Burdovsky's group, which demands money from the prince, and stays for one last conversation: he invites everyone to his funeral, weeps in the lap of the general's wife and, ashamed of having wept, shouts at the prince that he hates him more than all the rest. In the Explanation, before Holbein's painting, he sees nature as "a gigantic machine, of the most modern make," and says of the fly in the sunbeam that it "knows its place, loves it, and is happy, and only I am an abortion."
After the misfired shot, he is shamed by the guests' laughter and faints. In Part Four, he lives in Ptitsyn's house, tries to torment Ganya, and it is he who tells the prince that Nastasya will come to visit Aglaya. He dies two weeks after Nastasya.
There are two readings of the shot: Hippolyte forgot the cap on purpose, to be stopped and admired, or he really forgot, and the book punishes him with laughter. The prince recognizes in him his own weeping in Switzerland, before the lake and the mountains, when he felt excluded from the world's feast, and the difference between the two of them lies not in the experience but in what each did with it.