Season 1 · Episode 12
The Simpsons
Bart's TV hero Krusty the Clown is arrested for a convenience-store robbery, and witness Homer must testify against the clown.

A very widespread Latin American exclamation expressing surprise, shock, or mild frustration. It carries no vulgar meaning and can be used by speakers of all ages. Often heard on its own as a reaction.
A fixed phrase. 'Lío' (trouble, mess) is non-compositional here: knowing 'meterse' (to get into) and 'lío' separately does not reliably produce this idiomatic reading for a learner.
Widely used in Mexico as a strong affirmative. The literal words give no clue to this meaning. Common in casual speech among friends, but considered crude in formal settings.