The Secret Service doesn't want anyone messing with the president, even Mr. Met.

In an excerpt published in The Huffington Post this week from his new book, former New York Mets mascot A.J. Mass gives a behind-the-scenes (and an underneath the perpetually smiling baseball head) look at his job of cheering on the Major League Baseball team.

Mass's book is, Yes, It's Hot in Here: Adventures in the Weird, Woolly World of Sports Mascots. In it, he recounts a 1997 visit by then-President Clinton to Shea Stadium to mark the 50th anniversary of Jackie Robinson's first MLB game.

Mass, now an analyst for, writes he was working as Mr. Met at the time. A man wearing a dark suit, who Mass believed to be a Secret Service agent, gave him a stern warning before the game:

"We have snipers all around the stadium, just in case something were to happen," he says. "Like I said, do whatever it is you normally do. Nobody will bother you. But approach the president, and we go for the kill shot. Are we clear?"

"He pauses for a moment to let the words sink in, and it feels like he isn't only looking into my eyes, but also into my very soul with his blank, unblinking stare," Mass wrote. "Then he says the same thing again, only a little bit slower this time, making sure I know his warning is not in any way to be misconstrued as some sort of gag. He's dead serious, and if I don't believe him, then I'll be dead — seriously."

"Approach the president, and we go for the kill shot," he repeats. "ARE — WE — CLEAR?"