Rep. Steve StockmanSteve StockmanEx-GOP staffer pleads guilty to fraud, money laundering on behalf of ex-lawmaker Cornyn to run for reelection in 2020 Former congressman indicted on conspiracy charges MORE's (R-Texas) announcement that he would challenge the No. 2 Republican in the Senate, John CornynJohn CornynMcConnell names Senate GOP tax conferees Air Force makes criminal reporting changes after Texas massacre We need a better pathway for allowing civilians to move guns across state lines MORE (Texas), ignited Twitter — prompting surprise, intrigue and rebuke.

The freshman congressman has developed a wide social media presence, rankling some while igniting other conservatives with his strong criticism of President Obama.

News of Stockman's primary challenge broke around 8 p.m. on Monday. Both men were trending in D.C. soon after.

Stockman himself entered the conversation late, sending out a series of links to stories announcing his run.

Stockman started trending as the news first broke around 8 p.m.

Cornyn began trending shortly after.

Washington Examiner Online Editor Justin Green noted Stockman's prolific Twitter presence and his ability to get under some people's skin.

BuzzFeed's Washington Bureau Chief John Stanton harkened back to Stockman's decision to invite Ted Nugent to be his guest to the State of the Union earlier this year.

Democratic polling firm Public Policy Polling noted that a poll from last month showed Republican primary voters expressed interest in a more conservative candidate in Texas.

However, David Plouffe, President Obama's campaign manager in 2008, noted the short timeframe for Stockman to launch a serious challenge. The primary is slated for March 4, and early voting begins before that.

National Republican Senatorial Committee spokesman Brad Dayspring said Stockman would be defeated, noting Cornyn's conservative record.

Brian Walsh, a former NRSC spokesman, pointed out some of Stockman's liabilities early.

Political Wire's Taegan Goddard summed it up in blunt terms.

Cornyn's official office communications director underplayed the news.

But a spokesman for Cornyn's campaign did not pull any punches.