יהי לתנין. על שנתגאה ונקרא התנין הגדול נעשה לו אות מתנין ולומר מה נחש מתעקם והולך אף פרעה. ועוד הביא עליו נגע אחד וגו' לומר לו רשע היה לך להבין מפרעה הראשון שנתנגע על שעכב שרה וצער אברהם: יהי לתנין “it will turn into a serpent.” Seeing that Pharaoh had proclaimed himself as equivalent to a giant monster, G–d was going to show him Who it was that created such monsters. (Compare Ezekiel 29,3.) The principal feature of serpents is that they bend and twist, so Pharaoh would also be forced to bend and twist. (Sh’mot Rabbah 9,4) He also afflicted him with the plague of tzoraat, (Exodus 11,1) reminding him that he should have learned a lesson from what happened to the first Pharaoh when he tried to rape the wife of the first Hebrew, Avraham (Genesis 12,17).