The event was called “Shoot at Hurricane Irma,” and everyone was invited.

On Tuesday, Ryon Edwards of DeLand, Fla., created a Facebook event page about the imaginary gathering. In it, he called the hurricane “goofy” and added, in all caps, “LETS SHOW IRMA THAT WE SHOOT FIRST.”

At that time, the Houston metropolitan area was just beginning to recover after Hurricane Harvey. Irma was looming, just hours away from making its first landfall on the island of Barbuda.

Mr. Edwards’s show of comic bravado was a hit. His friends started signing on and making jokes.

Then a few strangers joined.

And then a few more.

On Sunday, more than 55,000 people had visited the page and expressed interest in attending.

Mr. Edwards, 22, who said he owns “a couple of rifles and a handgun,” is a welder and a bassist for a metal band called Gucci Flute. “I guess that a lot of people just connected to the joke, and the more it got shared, the more attention it seemed to get,” he said on Sunday.