The passuk says ובכל אלהי מצרים אעשה שפטים, “and with all the gods of Mitzrayim I will give punishment.” We don’t see in the Torah openly which gods were punished or how they were punished. What were the shefatim which Hashem did to their gods?
The Mechilta brings that it says shefatim twice; once here and once in Bamidbar- ובאלוהיהם עשה שפטים. This teaches us that there were separate punishments for each god; stone dissolved, wood rotted and metal gods became rusty. Some say a stone god rotted and a wood god melted. Shefatim teaches us not just different punishments but strange and out of the ordinary punishments. Yonasan ben Uziel brings there were 4 punishments: stone melted, metal rusted, wood was burnt, and pottery cracked.
The first makah struck the Nile river and turned it into blood. Rashi explains this is because the Egyptians worshiped the Nile since it was the water source for the entire Mitzrayim. Hashem first smote their god and afterwards the Egyptians!
The Menoras HaMe’or asks why was the korbon pesach from a lamb? He explains the Egyptians didn’t eat the lamb because it was their god. This is as the passuk says: כי תועבת מצרים כל רועה צאן. The Torah commands us to slaughter it, roast it completely, and eat it so the Egyptians should recognize and see their god judged in front of their eyes!
Also, in order for the Egyptians to recognize in the morning that Bnei Yisroel slaughtered a lamb, the Torah commands “do not break any bones!” They would see the bones and recognize that it was a lamb. Also, the Torah commands to take from the blood and put it on the doorposts in order to make known to all that Bnei Yisroel slaughtered lambs and did not care one bit about the Egyptians’ gods.
May Hashem help us learn from the unusual punishments to recognize His ruler ship and always remember Hashem is the One and only Master of all!