Utnapishtim tells Gilgamesh of a boxthorn-like plant at the very bottom of the ocean that will make him young again. Gilgamesh obtains the plant by binding stones to his feet so he can walk on the bottom of the sea. He recovers the plant and plans to test it on an old man when he returns to Uruk. Unfortunately, when Gilgamesh stops to bathe it is stolen by a serpent that sheds its skin as it departs, apparently reborn. Gilgamesh, having failed both chances, returns to Uruk, where the sight of its massive walls provokes him to praise this enduring work of mortal men. The implication may be that mortals can achieve immortality through lasting works of civilization and culture. Lines 1-203, Tablet XI  (note: with "supplemental sub-titles and line numbers added for clarity")        In addition to the flood story material, (lines 1–203), tablet XI contains the following flood story elements:  List of titled subparts, Tablet XI-(by Kovacs):  These are some of the sentences copied more or less directly from the "Atrahasis" version to the "Gilgamesh" epic: The Epic of Atrahasis provides additional information on the flood and flood hero that is omitted in Gilgamesh XI and other versions of the Ancient Near East flood myth. According to Atrahasis III ii, lines 40–47 the flood hero was at a banquet when the storm and flood began: "He invited his people ... to a banquet ... He sent his family on board. They ate and they drank. But he (Atrahasis) was in and out. He could not sit, could not crouch, for his heart was broken and he was vomiting gall." According to Tigay, Atrahasis tablet III iv, lines 6–9 clearly identify the flood as a local river flood: "Like dragonflies they [dead bodies] have filled the river. Like a raft they have moved in to the edge [of the boat]. Like a raft they have moved in to the riverbank." The sentence "Like dragonflies they have filled the river." was changed in Gilgamesh XI line 123 to "Like the spawn of fishes, they fill the sea." Tigay holds that we can see the mythmaker's hand at work here, changing a local river flood into an ocean deluge. Most other authorities interpret the Atrahasis flood as universal.