"Everyone Knows Juanita" is is a song from the 2017Disney/Pixar animated feature film, Coco. It is a song performed by Héctor, which he sings to Chicharrón in exchange for the latter giving the former the latter's guitar.
Well, everyone knows Juanita
Her eyes each a different color
Her teeth stick out and her chin goes in
And her...knuckles, they drag on the floor
Chicharrón: Those aren't the words!
Héctor: There are children present
Her hair is like a brier
She stands in a bow-legged stance
And if I weren't so ugly
She'd possibly give me a chance
Chicharrón comments in the fact that Héctor changed the lyrics to accommodate for Miguel's presence. The word "knuckles" was most likely supposed to be "knockers", in reference to Juanita's breasts.