Exodus 8:6

8:6 So Aaron extended his hand over the waters of Egypt, and frogs came up and covered the land of Egypt.

Exodus 7:19

7:19 Then the Lord said to Moses, “Tell Aaron, ‘Take your staff and stretch out your hand over Egypt’s waters – over their rivers, over their canals, over their ponds, and over all their reservoirs – so that it becomes blood.’ There will be blood everywhere in the land of Egypt, even in wooden and stone containers.”