Epic of Gilgamesh

"This plant, Ur-shanabi, is the 'Plant of Heartbeat', with it a man can regain his vigour."

"Gilgamesh found a pool whose water was cool, down he went into it, to bathe in the water. Of the plant's fragrance a snake caught scent, came up [in silence], and bore the plant off."

-The Epic of Gilgamesh, Tablet XI