Watch Blake Shelton Suck at Jimmy Fallon's 'Whisper Challenge'

"This is the stupidest thing I've ever been a part of," country singer barks at 'The Tonight Show' host

Jimmy Fallon continues his quest to embarrass Blake Shelton on national television. But anyone familiar with the comical country superstar knows that's going to take a lot more than a tongue twister… or bean dip tossing.

During his appearance on Thursday's Tonight Show, Shelton humored the host with a modern-day game of telephone, "The Whisper Challenge," which has become a viral trend on YouTube. The gist is, one person reads a name or phrase from a card while the other is listening to loud music on noise-cancelling headphones, and the latter guesses what the former is saying.

Fallon's first phrase, "pumpkin spice latte," resulted in the guess of another 'P' word from Shelton (and the anatomy discourse of a two year old). When the show host took a turn wearing the headphones, his guest was perplexed by the Oscar nominee's name on the card: Benedict Cumberbatch, who is up for Best Actor for The Imitation Game.

"That's a person? I've never even heard of that," Shelton admitted, repeating Cumberbatch's name over and over.

The singer then turned "Cobra Kai," the violent form of karate depicted in the iconic Karate Kid movie, into a bit of a staring contest with Fallon. And exhausted by the tomfoolery, Shelton declared, "This is the stupidest thing, literally, that I have ever been a part of in my career."

Still, "The Whisper Challenge" couldn't trump "Random Object Football Toss" in the ridiculousness department. Back in September, Fallon coaxed The Voice coach into throwing items including a mannequin head (which Shelton named "Alanis Morissette") and a bowl of seven-layer dip through a hole cut out of a cardboard football player.

"This is the dumbest thing I've ever done in my life," Shelton said during that challenge. But he fared a little better in it, beating Fallon 1—0. (Watch here.)

The country star was on The Tonight Show to promote this weekend's Saturday Night Live, on which he'll serve as both host and musical guest. Tune in Saturday at 11:35 p.m. ET on NBC.