Calendar Man (Julian Gregory Day) is a fictional supervillain appearing in American comic books published by DC Comics, as an enemy of the superhero Batman, belonging to the collective of adversaries that make up Batman's rogues gallery. Calendar Man is known for committing crimes that correspond with holidays and significant dates. He often wears costumes to correlate with the date of the designated crime.[1] In his debut, the character was presented as a joke villain, but in later years, writers developed Calendar Man as a dark, disturbed serial killer that toys with Batman.[2] The character will make his cinematic debut in The Suicide Squad, portrayed by Sean Gunn.[3]