美国超人有裤衩
[mĕi guó chāo rén yŏu kù chà]
Literally translated, it means 'American Superman Has Underwear,' which is a humorous take on the classic American superhero, Superman, who famously wears his underwear outside his pants, a detail well-known in global pop culture. The username might imply the user's familiarity with or interest in Western pop culture or could be making light-hearted commentary on how even iconic figures have mundane aspects.