L'Home dels Nassos is a popular Catalan character, who has as many noses as are left in the year. He only appears on December 31st so like everyone else, he only has one nose.
On the morning of New Years' Eve, children are traditionally told that there's a man in town who has as many noses as there are in the year and they obviously imagine someone with 365 noses on his face.
The parents then tell the children that the Home dels Nassos and they run out into the street to find him. It's very typical to have gangs of children running around the village streets trying to catch a young man dressed as the Home dels Nassos, who generally manages to stay just out of reach.
I've witnessed this on many occasions when we used to go and spend New Year with my first wife's parents in the tiny village of Capmany in the Alt Empordà in Northern Catalonia.
The tradition in Barcelona is a little more organised and the Home dels Nassos is a capgros, a figure with a large papier maché head (see the picture below) leaves the Llotja de Barcelona on Pla de Palau at 12 noon and then makes a tour around the streets of La Ribera.