How do you spell are you crazy in cantonese?

In Cantonese, "are you crazy?" is spelled as "你係唔係癲?" (pronounced as "nei5 hai6 m4 hai6 din1?"). Another common way to express it is "你瘋唔瘋?" (pronounced as "nei5 fung1 m4 fung1?"). These phrases convey the same meaning in a colloquial context.