Batman: There was once a man named Judah who had three sons.

Robin: His oldest son, Er, married Tamar, but then he died.

Batman: So Judah told his second son, Onan, to marry Tamar and give her a child to carry on the family name.

Robin: But Onan was wicked and refused to do what his father asked.

Batman: So God punished him and he died too.

The Joker: Ooh, sounds like someone else is going to have to step up and do the deed!

Batman: Yes...Judah told his remaining son, Shelah, to marry Tamar.

Robin: But Shelah was too young and so Judah refused to give his consent.

Batman: So Tamar decided to take matters into her own hands and she disguised herself as a prostitute and seduced Judah.

The Riddler: I'm guessing that didn't work out too well for him in the end?

Batman: No, it didn't. Tamar became pregnant and Judah was forced to accept her as his wife.

Robin: And she gave birth to twins, Perez and Zerah.

Batman: And so the line of David was born!