Billionaires, top tech CEOs and leading figures of the GOP establishment gathered on an island off the coast of Georgia this weekend for a conference where the main topic was how to stop Donald Trump, according to a new report.

The business and party bigs’ strategy sessions came at the American Enterprise Institute’s annual World Forum on Sea Island, The Huffington Post reported, citing sources familiar with the gathering.

Google co-founder Larry Page, Napster creator and Facebook investor Sean Parker, Apple CEO Tim Cook,and Tesla Motors and Space X honcho Elon Musk all attended, the website reported.

Also on hand were Senate Majority Leader Mitch McConnell (R-Ky.), Republican elder statesman Karl Rove, House Speaker Paul Ryan, GOP Sens. Tom Cotton (Ark.), Cory Gardner (Colo.), Tim Scott (S.C.), Rob Portman (Ohio) and Ben Sasse (Neb.), who recently made news by saying he could never support Trump.

The House was also represented by Energy and Commerce Committee Chair Fred Upton (Mich.), Rep. Kevin Brady (Texas) and Kevin McCarthy (Calif.), sources told the website, along with leadership figure Cathy McMorris Rodgers (Wash.), Budget Committee Chairman Tom Price (R-Ga.), Financial Services Committee Chairman Jeb Hensarling (Texas) and Diane Black (Tenn.).

Philip Anschutz, the billionaire GOP donor whose company owns a stake in Sea Island, also attended, as did Arthur Sulzberger, publisher of The New York Times.

“A specter was haunting the World Forum–the specter of Donald Trump,” William Kristol, editor of the Weekly Standard, wrote in a report from the conference, borrowing the opening lines of the Communist Manifesto.

“There was much unhappiness about his emergence, a good deal of talk, some of it insightful and thoughtful, about why he’s done so well, and many expressions of hope that he would be defeated. The key task now, to once again paraphrase Karl Marx, is less to understand Trump than to stop him.”

Rove presented focus group findings that Trump’s weakness was that voters have a very hard time envisioning him as “presidential” and as somebody their children should admire, the website said.

Trump, who is leading the Republican presidential race, can all but wrap up the GOP nomination by March 15 if he wins primaries in major states that include Florida, Ohio, Illinois, Missouri and North Carolina.