Water to blood, frogs and lice...
The Nile was worshiped, this was not an early morning stroll for Pharaoh - yet the waters as blood simply an inconvenience to him. 7 days he ignored this until it went away. Frogs were sent in challenge to Heqet, the magicians could also being forth frogs but not decrease them. Pharaoh entreats Moses to rid of the frogs with the promise to let the Israelite's go, then retracts his promise once the frogs are gone. So next comes the lice in challenge to Seb - the magicians at this pint recognise it is God and tell Pharaoh in v19 this is the finger of God, yet again Pharaoh hardens his heart and listened not. What do you think Pharaoh was thinking by now?