SÃO PAULO—It has been likened to a hand grenade with brass knuckles, ridiculed as a "glorified rattle," and dismissed by one British sportswriter as "rubbish."

Meet the caxirola, Brazil's answer to the vuvuzela, the elongated plastic horn that sounded like a bellicose water buffalo and was unleashed on mankind's eardrums during the 2010 World Cup in South Africa.

"If...