Outside of the segment on Trump's indictments and his behavior on Jan. 6, it's been a bit surprising that there's been little discussion of him otherwise. There've been a few references to actions taken prior to Biden taking office, indirectly involving Trump, but not much specifically about him. That has turned this debate into something of an alternative universe where these are the main eight candidates, not the eight who are badly trailing the main guy not in the room.
-Analysis by Geoffrey Skelley of FiveThirtyEight

Yeah, Maya, I am surprised Trump didn’t come up more. With him not on stage, I actually thought it would be easier for the candidates to swipe at him, since there was no risk of him punching directly back. But with some notable exceptions, like Christie and Hutchinson (and even then, only on a couple occasions), the candidates showed little interest in hammering away at the primary front-runner. I think that’s a questionable strategy since none of these candidates will be able to earn majority support in the primary without stealing some of it from Trump.
-Analysis by Nathaniel Rakich of FiveThirtyEight

Sixty-eight percent of Americans think the government is withholding information about UFOs, and three-fourths think there is some form of life on other planets. The number of Americans who suspect UFOs have been spotted has also increased, and 41 percent believe that some spotted UFOs are alien spacecraft. This has only been increased in recent years with Navy pilots reporting strange sightings over the past decade, along with recent congressional hearings about the issue.
-Analysis by Monica Potts of FiveThirtyEight

Christie was seen smiling and shaking his head as Fox News moderator Martha MacCallum began to ask about UFO ecounters.

"I get the UFO question? Come on, man!" Christie said.

"I think it's horrible that just because I'm from New Jersey, you asked me about unidentified flying objects and martians," he continued. "We're different but we're not that different."

Trump teased for months whether or not to attend the first GOP primary debate, citing along the way his yawning leads in early national and statewide polls.

"Why would I allow people at 1 or 2% and 0% to be hitting me with questions all night?" he said in an interview in June with Fox News anchor Bret Baier.

When he ultimately decided to not appear on stage on Wednesday, it was precisely that lead he cited.

"The public knows who I am & what a successful Presidency I had," Trump wrote on social media, adding, "I WILL THEREFORE NOT BE DOING THE DEBATES!"

It also appears unlikely that Trump will attend the second debate hosted next month by The Ronald Reagan Presidential Foundation & Institute, the administration of which Trump has feuded with in the past.

"He's not going to be in California," senior Trump campaign adviser Chris LaCivita said on the conservative "Ruthless" podcast Wednesday. "Well, first of all, with President Trump, you know, he could change his mind at any moment. Right. But I think he said the other day, he should take his history for face value when he said debates, right? And you should just assume that he won't until he does."

-ABC News' Tal Axelrod