Facebook founder Mark Zuckerberg likes to take on "personal challenges." In 2009, he hung up his trademark hoodies and wore a tie every day. Last year, he resolved to learn Chinese. This year, he's sworn off meat unless he's killed the animal himself. Zuckerberg's "odd dietary direction" emerged via a May 4 status update informing his Facebook friends that he'd killed a pig and a goat. In an email to Fortune, the 27-year-old explains that his decision gelled after guests at a Zuckerberg-hosted pig roast told him that "they really didn't want to think about the fact that the pig used to be alive." That seemed "irresponsible" and Zuck vowed to learn more about his food's origins. Now the billionaire is "basically" a vegetarian — in between slaughters, that is. Predictably, this revelation has inspired biting remarks. Here, a sampling:

The secret to his success
"Mark Zuckerberg has certainly been called cutthroat before, but nobody meant it literally," says Nick Fox in The New York Times.

The next big thing?
"Somehow we don't think this will catch on quite like Facebook did," says Megan Gibson in TIME.

Private parts
"Zuck's caveman ambitions first came to light when he updated his status to 'I just killed a pig and a goat' on Facebook," says Nitasha Tiku in New York. "We haven't reached the vaunted status of being one of his 847 'friends'" yet, but we're pretty sure he added, 'And I then I stole their privacy. What what!!?!'"

Next up
"Zuckerberg says that he is interested in going hunting. So watch out, deer. You're likely next on the hit list," says Andrew Couts at Digital Trends.

Big game
"We're OK with" Zuckerberg hunting, "as long as it doesn’t turn into another GoDaddy CEO/elephant-killer situation," says Jennifer Bergen at Geek.com.

Never satisfied
Of course Zuckerberg is doing this, says Robert Quigley at Geekosystem, "because founding and expanding a multibillion-dollar company in his 20s apparently wasn’t hard enough."