The Posthumous Memoirs of Bras Cubas
Bras Cubas is one of the weirdest books I've read in a while and it doesn't feel like it was written in the 19th century. Published in 1881, the novel has a unique style of short, erratic chapters shifting in tone and style. Instead of the clear and logical construction of a normal nineteenth-century realist novel, The Posthumous Memoirs of Bras Cubas (full title) makes use of surreal devices of metaphor and playful narrative construction. It is considered the first romance of the realist movement in Brazil.
The novel's form reminds me a bit of Tristram Shandy. Both have a fractured narrative style and some experimental usages.