Utnapishtim is a character in Mesopotamian mythology who survives the great flood sent by the gods to destroy humankind. He survives this tragic event due to the help of the god Enki. This deity advises Utnapishtim to build a giant ship to house his family and a female and male of all animal species. When the flood ends, Utnapishtim releases the animals in order to repopulate the earth. The gods were eventually thankful that Utnapishtim had restrained them from destroying all life forms. To show their gratitude, they rewarded Utnapishtim with immortality.
Utnapishtim also stars in the Gilgamesh epic. In his quest for immortality, the legendary king of Uruk visits Uthnapishtim to uncover the secret of eternal life. Utnapishtim directs Gilgamesh to a special plant that is to grant him immortality. Due to some unfortunate events, Gilgamesh manages to squander this gift.
Note: Utnapishtim (Sumerian mythology) and Atrahasis (Akkadian mythology) are one and the same.