What creature deceived Eve in the Garden of Eden?

Answer: A serpent

The serpent, more crafty than any beast of the field, tempted the woman. She told God, "The serpent deceived me, and I ate."

“Now the serpent was more crafty than any beast of the field that the LORD God had made. And he said to the woman, “Did God really say, ‘You must not eat from any tree in the garden?’” Then the LORD God said to the woman, “What is this you have done?” “The serpent deceived me,” she replied, “and I ate.””— Genesis 3:1, 3:13 (BSB)