As Seth Meyers began his show Tuesday night mocking President Trump’s Oval Office meeting with House Minority Leader Nancy Pelosi and Senate Minority Leader Charles E. Schumer, the late-night host had one question for his audience. “What is Mike Pence doing?” Meyers asked.

During the day, Trump and Vice President Pence were joined by the Democratic leaders for a cordial photo op that swiftly turned into a heated argument — described by The Washington Post’s Erica Werner and John Wagner as a “stunning public spat” — over funding for the president’s border wall and the looming possibility of a government shutdown. For 17 minutes, in front of reporters and other White House staff, Trump, Pelosi and Schumer squabbled, making pointed remarks and talking over one another. But one person was noticeably absent from the melee: Pence.

Beyond an occasional slow nod and blinking, a silent Pence sat largely motionless in a buttercup yellow armchair next to the president, his face void of emotion as the intense debate raged around him. Pence’s behavior, or lack thereof, instantly caught the attention of social media users and late-night hosts.

“I guess when Schumer said ‘shutdown,’ Pence took him literally,” Meyers quipped.

On CBS, Stephen Colbert kicked off his show with a cold open that aimed to shed light on the day’s mystery: Just what exactly was going on in Pence’s head?

The sketch begins with a clip of the meeting showing Trump and Schumer in the middle of arguing. The video then zooms in on Pence, as low and dramatic music plays.

“I wonder if I sit real still if people will even notice I’m here,” a man’s slow drawl says in a voice-over, narrating Pence’s internal monologue. “I’m a manila envelope taped to a beige wall. No one can see me.”

The internal voice then has Pence ruminating about his thoughts on gay people, “I don’t think all gay people all bad, I just think all bad people are gay,” and what he wants for dinner — “Maybe rice? Nah, too Asian. Boiled potatoes it is.”

“Hmm, President Pence,” the voice-over says as the real-life Pence nods. “The Pence administration. The Michael Pence Presidential Library and Casino.”

In the cold open’s final clip, a brightly colored sombrero adorns Pence’s head. “Nobody even noticed,” the voice laments.

For Trevor Noah and Jimmy Kimmel, Pence was the highlight of the Oval Office meeting.

Noah told his audience on “The Daily Show” that Pence was his “favorite part of this awkward threesome.”

“He just sat there motionless, like a guy whose edibles just kicked in,” Noah joked, before pretending to be stoned, blinking slowly with his mouth slightly agape.

Noah also speculated on what Pence was thinking about.

“He was probably just daydreaming about whatever it is that Mike Pence daydreams about,” Noah said. He then showed edited footage of the meeting in which a cartoon thought bubble popped up next to the vice president’s head. Inside the bubble, a clip from the TV show “The Handmaid’s Tale” played. (Pence has been protested at least twice this year for his views on women’s reproductive rights by people dressed as characters from the popular Hulu series, HuffPost reported in August.)

“Yeah, that seems about right,” Noah said.

Kimmel, who said the Oval Office spectacle could be the beginning of a new reality TV franchise called “The Real White Housewives of D.C.,” hailed Pence as the “the best part of the meeting.”

Pence, Kimmel said, was “just sitting there quietly, patiently waiting to be president, not saying a word.”

On social media, observant users instantly took notice of the vice president, who appeared to be trying his very best to be invisible.

“Can someone please check to see if Mike Pence is actually still alive or is this a ‘Weekend at Bernies’ type scenario where they just prop up Pence at meetings,” one Twitter user wondered, referencing the 1989 film in which two friends have to convince people their dead boss is still alive by manipulating his corpse.

Others compared him to an “Elf on the Shelf” toy and a Madame Tussauds wax figure.

“This holiday season who needs ‘Elf on the Shelf’ when you have ‘Pence on a Chair,’” one person tweeted.

Many ridiculed Pence for taking what The Post’s Aaron Blake described as “the potted-plant approach” to the meeting. Sharing a picture of a flat, gray rock, one Twitter user wrote, “Things as useful as Mike Pence."

Hours later, one person expressed concern for the vice president, tweeting, “Has anybody told Mike Pence it’s okay to move yet or is he still there, in the dark?"