There is a rhyming couplet strongly associated with Quaquaval, especially in those parts of the world where these pokemon are not commonly found:
"Dance, dance, the carnival of ducks!
Quaquaval has come and it brings good luck!"
This phrase is known around the world, from Alola to many parts of Paldea where these pokemon are no longer seen, as a nursery rhyme told to children, and has been fixed with that particular phrasing. It was not always so. The line "carnival of ducks" appears in all variations – curiously so, given that Ducklett's range does not overlap much with Quaquaval's, Psyduck's (which shares only a bill shape with the true ducks) even less so, and the order were once known in much of the world, before modern scientific nomenclature, as "quacks". Furthermore, only a single Quaquaval was ever needed for (or indeed, often appeared at) the festival, and the singular would produce a closer rhyme.
The second line has a number of variations, from the bawdy "and it's time to fuck", recalling their festivals as a time when young men and women would get together, to the sinister "and you're out of luck", which speaks to either the violence which sometimes accompanied Quaquaval carnivals, or an alternative tradition holding that the arrival of these pokemon was a maddening curse.
The spontaneity of the old carnivals, when the random appearance of this pokemon would cause a crowd to break out in dance, is long gone. Today, the carnival of ducks is scheduled annually for a spring Monday, and municipalities contract with trainers to ensure an actual Quaquaval is present. Yet these pokemon still energize crowds with their dancing, leg kicks, and beautiful water displays, and inspire them to join in – just as they have done for hundreds of years.