Which Iranian festival includes the prank custom dorugh-e Sizdah?

The Iranian festival associated with the prank custom dorugh-e Sizdah is Sizdah Bedar.

Sizdah Bedar is celebrated on the 13th day of Farvardin, the first month of the Iranian calendar, as part of the Nowruz season. Its name is commonly understood as referring to going outdoors on the thirteenth day, and the holiday is also known as Nature Day because families traditionally spend it in parks, countryside and other natural settings.

Dorugh-e Sizdah means “the Lie of the Thirteenth.” Similar to April Fools’ Day, it involves telling a convincing lie or playing a prank. The date usually falls around April 1 or 2 in the Gregorian calendar, although the relationship changes because the Iranian and Gregorian calendars do not align in a fixed way.

Sizdah Bedar has other customs that can cause confusion. Families may picnic, eat foods such as lettuce with sekanjabin, and throw sprouted greens from the Haft-Seen display into moving water. Knotting the greens while making a wish is another tradition. Charshanbe Suri and Yalda Night are separate Iranian festivals, while Nowruz is the larger New Year celebration of which Sizdah Bedar forms a part.