Learn Spanish (Latin America): Este calzado me dio una ampolla gigante.

To sound more dramatic, you could say una ampolla de locos (a crazy big blister) or una ampolla de terror (a terrifying blister). While gigante is a standard adjective, using a de + noun phrase replaces it with a native-sounding, extreme exaggeration.

Why use me dio (it gave me) instead of a verb for "to get"?

In English you "get" a blister, but Spanish rarely uses literal translations for "get" (like obtener or conseguir) for physical ailments. Instead, the object "gives" it to you. This is the same structure used for emotions or reactions, like me dio alergia (it gave me allergies) or me da miedo (it scares me).

What's the difference between using este calzado and estos zapatos here?

Zapatos specifically means "shoes" and is a countable plural. Calzado is a broader, singular category word meaning "footwear" (which includes boots, sneakers, sandals, etc.). You'll often see calzado used in retail or formal contexts, but it works perfectly in everyday speech to refer to whatever is on your feet.

Since ampolla is feminine, shouldn't it be una ampolla giganta?