Rabbi Jochanan said: All the dead will arise at the resurrection of the dead, except the generation of the Flood, as it is said, "The dead shall not live, the deceased (Rephaim) shall not rise" (Isa. 26:14). "The dead (who) shall not live" refer to the heathens, who are like the carcase of cattle; they shall arise for the day of judgment, yet they shall not live; but the men of the generation of the Flood, even for the day of judgment they shall not arise, as it is said, "The Rephaim shall not rise" (ibid.).
All their souls become winds, accursed, injuring the sons of men, and in the future world the Holy One, blessed be He, will destroy them out of the world, so that they should not do harm to a single Israelite, as it is said, "Therefore hast thou visited and destroyed them, and made all their memory to perish" (ibid.).