This phrase is used informally to describe someone or something as being very ugly or unpleasant. It literally translates to 'he/she/it is uglier than a drug case', which is an exaggerated way of saying someone or something is extremely unattractive or distasteful.
Examples
- Spanish: No me gusta ese edificio, es más feo que un caso de drogas.
- English: I don't like that building, it's uglier than a drug case.