Figaro! :) The word is "Figaro!" and it is a line from the baritone aria "Largo al factotum" from Rossini's Barber of Seville. He hits your line about 3:20. He's Figaro, he's singing to himself, pretending people are calling his name demanding his various services. Hard to say why that's the one people reach more for than others, other than it's a very very popular opera, and that's probably the most memorable aria from it... Also, most men are in a baritone range so it sits well for the voices of a lot of people who may wish to be silly, and it's not a very hard aria to give a go, the Italian is also very Italian 201 level stuff. Also Bugs Bunny sang it.