Alarmingly under-sized in a sport of blood-curdling giants, Carroll had to sign a death waiver before entering the sumo world championships. But the skinny Cork native, the first man from Ireland to take part in the tournament, tweaks the nose of fear.
"The Japanese weigh-in guys laughed at me," Carroll told Reuters before Sunday's tournament in Sakai. "But the bigger they are the harder they fall. If you think anyone small can't make a difference in life then think of a mosquito in your bedroom. That's my sumo name -- Green Fly. I'm the little mean green sumo machine."
Carroll only squeaked into the championships because his "mawashi" -- or "nappy" as he prefers to call it -- carried him over the minimum 75-kilogram weight limit.
"In true Irish fashion I came in at 74.9 kilos," he laughed. "You have to be 75 kilos to actually compete so thank God my sumo nappy weighed five kilos. I got in by nappy default."
Carroll, comfortably the lightest wrestler in the amateur competition, barely flinched when tournament organisers pushed a death waiver under his nose.
"I had to sign something about (them having) no responsibility for injury of any kind," the Irish braveheart winced. "What does that mean? True to form misunderstanding has meant I might have signed my life away."Carroll caught the sumo bug by freakish chance after winning a surprise gold medal at the world elephant polo championships in Nepal last year.
"I was riding home in December last year through the Nepali jungle with my world elephant polo trophy under my arm looking at the arse of the elephant in front of me," he smiled.
"I thought if that arse had a G-string on it, it would be a sumo wrestler. So immediately the idea, in the Nepali jungle, was born."
Carroll, who has popped up in previous incarnations as a tennis coach in Germany and a bobsleigher in Latvia, unveiled his cunning strategy for sumo success -- an old-fashioned headbutt.
"I'm just a scrawny little six-foot guy," he said, elaborating that his inspiration was Zinedine Zidane's infamous butt on Marco Materazzi in this year's World Cup final. I'm going to do what I call the 'bull-frontal'. In short, I've clicked that the best way to fight for a small guy is to do a Zizou on them, the bull-frontal."
Carroll added with a laugh: "I'm going to try to knock them out -- go straight in with the crown of my head first. Zizou got a medal. I'm doing the bull-frontal too."