Historical clue formulations

• Prone to sarcasm — 2018-10-06
• Wryly amusing — 2016-01-16
• Slightly twisted — 2003-08-07
• Not straightforward — 2001-08-24
• Like Oedipus's curse in "Oedipus Rex" — 1997-03-28
• Mocking — 1997-03-15