Almost every cheap snack bar in Brazil serves a version of X-Tudo, a burger with several toppings.
The name X-Tudo can be translated literally as "cheese-everything". The term comes from the word cheeseburger - since ch in Portuguese sounds like sh in English, the word "cheese", when mispronounced by a Brazilian, sounds almost like letter X (xis).
Snack bars abbreviate cheeseburgers as X-burger on their menus. Dozens of variations stem from the term, such as X-salada (a cheeseburger with lettuce and tomato) or X-frango (a "chicken breast burger" with cheese)
What's in a X-Tudo? Typically, what's in the version sold by Diskburguer, a snack delivery in São Paulo: bread, a hamburger patty, cheese, a fried egg, tomatoes, lettuce, vinaigrette, bacon, onions and mayo.
While some Brazil burgers can be targeted at a sophisticated clientele, the authentic X-Tudo is casual and cheap. Never buy it from street vendors, though - stick with reliable bakeries and snack bars.
São Paulo, home to several of the best burger places in Brazil, is also home to a X-Tudo challenge. Santa Coxinha, which specializes in chicken croquettes, makes the Ultra X-Tudão (at a menacing 7,500 calories). Here's a photo on Flickr.
Danilo Big Lanches, a snack bar in Sorocaba, came up with an even larger challenge (the winner eats for free and gets a money prize). As of this writing, nobody has won.
The term X-Tudo, implying variety, was the name of a popular children's program on Brazilian educational TV and has been used as a nickname for a package of laws issued by São Paulo mayor Gilberto Kassab.