Watch the Obama joke everyone is talking about from the DNC

• GOP nominee Donald Trump loomed large in Barack Obama's speech at the DNC on Tuesday.
• Obama slammed Trump's "weird obsession with crowd sizes" while making a suggestive hand gesture.

Former President Barack Obama tore into GOP nominee Donald Trump during his speech at the Democratic National Convention on Tuesday.

Obama took multiple swipes at Trump during his address, calling him a "78-year-old billionaire who has not stopped whining about his problems since he rode down his golden escalator nine years ago."

And while Obama is known for his oratory brilliance, it was the combination of his rhetoric and a suggestive hand gesture that made one of those jabs go viral.

"It has been a constant stream of gripes and grievances that's actually been getting worse now that he's afraid of losing to Kamala," Obama said about Trump.

"There's the childish nicknames. The crazy conspiracy theories. This weird obsession with crowd sizes," he added, while drawing his hands together to indicate he was referring to a small size. He paused for a beat after delivering the comment and looked down at his hands before gazing deadpan into the audience.

The suggestive gesture drew laughs from the audience and speculation from people online.

"Did he just make a size joke?" a person with the X handle @monica_adams1 wrote in a post about Obama's speech.

"This is going to haunt Trump for the rest of his miserable life," another user with the handle @acnewsitics wrote in a post with a screengrab of Obama's hand gesture.

Representatives for the Trump campaign didn't immediately respond to a request for comment from Business Insider sent outside regular business hours.

It's not the first time Trump has faced a size joke while on the campaign trail.

During the 2016 presidential campaign, Sen. Marco Rubio of Florida made a comment about the size of Trump's hands during a campaign rally in Virginia.

"And you know what they say about men with small hands? You can't trust them," Rubio said.

"He referred to my hands, 'If they're small, something else must be small.' I guarantee you there's no problem. I guarantee it," Trump said in response during a presidential debate with Rubio days later.

To be sure, Obama's speech wasn't just about making fun of Trump. Obama reminded his supporters that Trump could still prevail in the election in November.

"For all the incredible energy we've been able to generate over the last few weeks, for all the rallies, and the memes, this will still be a tight race in a closely divided country," Obama said.