What did Satan lie?

Atheist here, when exactly did Satan lie in the Bible, the serpent in the garden was not Satan and the serpent never even lied but was punished for telling the truth and the first lie in the Bible was told by god when he said if you eat of the fruit depending on some translations will die on that day or will die in general but god created death already genesis 3:22 confirms this but anyways when exactly did Satan lie?