America's Got Talent's 'worst act' ever has judges recoiling in disgust

America's Got Talent is a series that showcases a wide range of acts - among them are tear-jerkers, death-defiers and cringe-inducers.

So it takes someone - or something - fairly special to have Simon Cowell call it "the worst act we've had".

Cue Sethward, the comedian dressed as a caterpillar, in what can only be described as an up-cycled sleeping bag.

Making his entrance with a face-plant, he writhed around with reckless abandon, almost falling off the stage as the judges appeared increasingly concerned.

It was probably ambitious of Simon to expect a straight answer to the question, "where are you from?"

"I'm from the forest, where I live among all the beautiful creatures!" Sethward beamed.

Former Spice Girl Mel B couldn't repress a groan and an eye-roll as the crowd began to boo.

"Whatever you're going to do, get on with it and make it quick," said Simon.

Sethward eventually began his performance, which involved retreating into his sleeping bag and metamorphosing into a cocoon.

At this point, Mel B needed a short biology class refresher, asking fellow judge Howie Mandel, "He's going to... what do caterpillars turn into?"

All four judges hit their buzzers as Sethward yowled in pain about how difficult it was to reach his final form, bringing his act to a grinding halt.

Things only got worse as he stood on stage in a state somewhere between caterpillar and butterfly, left somewhat exposed in the process.

"There's a hole in your stockings!" judge Hedi Klum said, cringing, while Mel B branded the stunt "inappropriate".

"You made me come out too early!" replied Sethward.

While the judges panel was rendered nearly speechless, Simon wasted no time putting everyone out of their misery.

"Sethward, this is the worst act we've had. It's four 'no's, goodbye."

Despite the stinging rejection, it took host Tyra Banks appearing with a can of bug spray to remove Sethward from the stage.

Sethward's full performance - along with many much better ones - can be watched as the new season of America's Got Talent starts Saturday, August 4, at 7pm on Three.