Water of Bitterness:. The Hebrew word for this series of words is "Marah"
They arrived at Marah but couldn’t drink the water there, because it was bitter. This is why they called it Marah [bitterness]. The people grumbled against Moshe and asked, “What are we to drink?” Moshe cried to Adonai ; and Adonai showed him a certain piece of wood, which, when he threw it into the water, made the water taste good. There Adonai made laws and rules of life for them, and there he tested them. He said, “If you will listen intently to the voice of Adonai your God, do what he considers right, pay attention to his mitzvot and observe his laws, I will not afflict you with any of the diseases I brought on the Egyptians; because I am Adonai your healer.” (A: v, S: iv)
Sh'mot (Exo) 15:23*-26 CJB
https://bible.com/bible/1275/exo.15.23-26.CJB
https://en.wikipedia.org/wiki/Marah_fabacea
The tubers of Marah fabacea were crushed and thrown into surface waters by the Kumeyaay to immobilize fish. The tubers contain megharrhin, a saponin-like glucoside. Saponins lower the surface tension of water allowing the formation of bubbles. It is likely that the substance enters the fish's circulation through the gill arches where only a single-cell epithelium separates the water from the animal’s red blood cells. The affected fish float to the surface.[3]
The fish walk on water.