Raise your hand if you had the infamous London serial killer on your debate bingo card.
What was that, again? During Sunday's Democratic debate between former Vice President Joe Biden and Vermont Senator Bernie Sanders, Biden mentioned famed London murderer Jack the Ripper, then never completed the thought. Naturally, social media users were eager to speculate on exactly where the candidate was going.
As the debate came to an end, the candidates scrapped over their opinions on authoritarian regimes, sparked by a moderator question to Sanders about his past comments on Cuban dictator Fidel Castro. When the conversation moved from Cuba to China, Sanders asked his opponent, "Did China make progress in ending extreme poverty?"
That led to Biden invoking Jack the Ripper, a yet-unidentified serial killer who may have murdered more than five women in England around 1888. "That's like saying Jack the Ripper ..." Biden began to say, perhaps meaning to say that good qualities can't redeem actively evil people or regimes. Emphasis on the perhaps. Sanders seemed to anticipate where the former veep was going, disagreed, and Biden never completed his simile.
Social media users wanted to know more. "OK, but how was Biden going to finish 'that's like saying Jack the Ripper...'?" one Twitter user asked.
Wrote another, "I'd pay good money for the end of that Jack The Ripper analogy by Biden."
Some commented on how unlikely it was to have a reference to the famed killer pop up during a political debate. "If you predicted, 'Biden makes an allusion to Jack the Ripper at the debate,' I have a crisp fiver for you," one Twitter user wrote.
Some just made up an explanation. "Didn't watch the debate so I'm just going to assume Biden was revealed to be Jack the Ripper and I just want everyone to know that I will not vote for a man who terrorized the impoverished Whitechapel district of London in 1888," one person wrote.
And the mere fact that a merciless historical murderer was briefly trending on Twitter was enough for some to comment.
"Jack the Ripper is trending," wrote one Twitter user. "I thought he died but it turns out he's just hiding inside a horse and oh my god he's covered in knives oh no he's throwing a wagon wheel wait is he a VAMPIRE?"
Biden wasn't the only candidate who made headlines for a meme-able remark he delivered at the debate. Sanders earned some buzz for calling video-streaming site YouTube "the YouTube."