This is not really a mask, but more like a "lurid popular caricature", what was called in Venice at the time, a "maschera barona" (a plebeian mask), that went on in Venice for quite some time in the XVIII century.
Bernardon was this old guy all bandaged up, with scars and sores, stopping at the café tables where people were spending their time, asking for money.
He pretended to be affected by the "French Disease" (syphilis) for having had exaggerated sex experiences without any restraint.
Bernardon is taken around, sings foul songs and begs for money, with a bandaged head and a body full of sores.
"Povero Bernardon tuto impiagao!
Col baston son redoto, e pien de fame,
a pianzar per la strada el mio pecao
che tuto intiero m’à imarzio el corbame;
causa ste scarabazze, e la so scuola,
so sta butao ne la quinta cariola."
"Poor Bernardon, full of sores!
I can't walk without a stick, and I'm full of hunger,
here I am crying about my sin
that has completely damaged my skeleton;
because of these women of sin, and of what they done me
I have been thrown sick in this deep misery."
The wheelbarrow may be a physical representation of the idea of "quinta cariola", being the cariola how the wheelbarrow is called, so it becomes a word joke inside the tease. But this is my interpretation.
Some historians see in Bernardon a disguise set up by the government to moralize Carnival: not sure if it worked as it was supposed, though.
Anyways the Bernardon disguise was banned in 1815 by the second Austrian Government.
