As we look forward to the @CNN debate Tuesday, the immortal words of the Riddler, Batman's colorful nemesis, ring true.
The first CNN debate in September was a relatively tame affair -- or as tame as a debate featuring Donald J. Trump can be. The candidates were establishing their messages and their places in the race.
Jeb Bush, still thought to be a principal contender, was featured center stage, next to Trump. Ben Carson, on Trump's other side, had not yet begun his rocket ride up -- and down. Ted Cruz and Marco Rubio were on the flanks.
In the ensuing two months, Trump's support has strengthened if not grown, helped by his limitless gall and by terrorist attacks that have created a greater market for his strongman appeal.
Bush, beset by miscues, the weight of his family legacy and Trump's withering assault on his diffident style, has faded. And Cruz and Rubio -- a pair of freshman senators with similar profiles but distinct approaches -- are on the rise.
With less than 50 days to go before the Iowa caucus, the GOP race is taking shape. The starting line is within sight. And so Tuesday's final GOP debate before the holidays and election year promises to be the most intriguing and contentious yet.
Here are the things I'll be watching for:
How do they navigate Trump?
As The Donald has noted, those who have launched direct attacks on Trump have generally fared badly. Rick Perry was the first to lash Trump as a plague on conservatism. One suspects the former Texas governor's eagerness to engage was prompted by his own failure to connect with voters. If so, the gambit failed badly. He was the first out of the race.
Bush, Carly Fiorina, senators Rand Paul and Lindsey Graham and Gov. John Kasich of Ohio all have taken turns tangling with Trump, fetching gleefully brutal rejoinders from a frontrunner with an uncanny instinct for the jugular.
Trump also has cast all his attackers as exemplars of a Republican establishment that is reviled by the activist wing of the GOP.
Perhaps not entirely by coincidence, the three contenders who have shown some positive movement in recent polls have been those who have tried to steer clear of Trump -- Cruz, Rubio and Gov. Chris Christie of New Jersey.
Cruz, who has plotted his race brilliantly, has made quantum leaps, seizing a 10-point lead over Trump in the latest Iowa Poll. He has done it by methodically organizing among the social conservatives and tea party and, in his own words, killing Trump and Carson with kindness, waiting for their collapse to pick up the pieces.
Carson appears to have cooperated. His precipitous drop in Iowa and nationally after stumbling on national security issues clearly has redounded to Cruz's benefit.
But Trump remains a stubborn obstacle to Cruz's plan to coalesce the anti-government populists.
Is the Trump-Cruz bromance over?
With Cruz now nipping at his heels -- and dissing The Donald in private fundraising meetings, a recording of which surfaced last week -- will Trump aim his missiles at Cruz on Tuesday night? And if he does, will Cruz quit the bromance and fire back?
Cruz and Rubio also have been spatting, as the reality crystallizes that they may be headed for a showdown.
If Cruz hopes to emerge as the candidate of the aggregated forces of the right, Rubio has emerged as a potential life raft for the GOP's establishment forces, who have seen the Bush battleship and Kasich schooner take on water.
To date, Rubio has played the game more artfully than any, maintaining his standing with all factions of the GOP -- the establishment, social conservatives and tea party.
Will Cruz or Trump try and split the anti-establishment forces try and prosecute Rubio for his abortive collaboration with a bipartisan group of senators on immigration reform?
Will Bush or Kasich, desperate to get back into the game, shoot at Rubio for being scared off of his immigration positions?
Terrorism a top concern
Another change since September: The terrorist attacks in Paris and San Bernardino have profoundly changed the backdrop for this debate. Terrorism and national security have jumped past the economy to the top of the list of voter concerns, at least for now.
Trump's bellicose response -- first to bar Syrian refugees and then all Muslims -- created a furor but did nothing to diminish his support. He's sure to be questioned closely on this Tuesday night, and may welcome it. Polls shows that while a majority of Americans oppose his stances, a majority of Republicans support them.
Rubio, a self-styled national security hawk, has targeted Cruz, after the Paris attack, for supporting changes in the collection of phone and Internet data that Rubio says imperil the country.
For Rubio, the national security attack is a way of getting to Cruz's right without jeopardizing his own standing with establishment Republicans.
Expect to hear more of this on Tuesday.
The Christie factor
While Christie continues to lag in national polls, he has encamped in New Hampshire, received the blessing of the Manchester Union-Leader and has risen to second place behind Trump in the state that will host the first-in-the-nation primary.
Christie, a former prosecutor, has, as much as any of the candidates, seized on terrorism, vowing muscular leadership.
A strong showing for Christie in New Hampshire may not propel him into the upper echelons of the race, given his lingering baggage of New Jersey scandals and fiscal woes. But it could spell doom for establishment candidates like Bush and Kasich and make Rubio's path more difficult.
Will anyone raise the specter of Jersey on Tuesday, or will the debate-seasoned Christie escape another event without injury?
There will be nine candidates on the main stage Tuesday. But these are the four I'll be watching: Trump, Cruz, Rubio and Christie.
It's almost the New Year. The starting gun is approaching. It's time for the players to make their moves.