This is a colloquial expression used in some Latin American countries. It translates literally as 'he/she has become like a toad in a latrine.' It is used to describe someone who has become very angry or upset.
Examples
- Spanish: Cuando se enteró de que había perdido su empleo, se puso como sapo de letrina.
- English: When he found out he had lost his job, he became as angry as a toad in a latrine.