Even Haman got fooled by this day.
Today is the Birth and Death of the only man that knew G-d face to face, Moshe Rabbeynu. His true stature is sadly unknown and underappreciated outside of Judaism. The Midrash Raba mentions the powerful account of the last hours before his death and how the satan wanted to claim his body. It is in this account where we see how (and why) the most humble man yielded such tremendous power. This pure piece of Oral Torah is even referred to in the Christian Book of Jude.
When Haman casted the Pur, he was told that Moshe died in this month. This was a great motivator for him to choose this month for his plan of annihilating the Jews. He however did not know that Moshe was also born on this day. The truly righteous die on the date they were born. They have the merit to come full circle. True to Adar character, this hidden fact turned Haman's plan on himself.