Final answer:
The unusual aspect of Santiago's dream is that it involves talking animals, adding a surreal element to the story.
Step-by-step explanation:
The strange or unusual aspect about Santiago's dream in 'The Old Man and the Sea' by Ernest Hemingway is that it involves talking animals. Unlike typical dreams which may be influenced by daily events or subconscious thoughts, the presence of talking animals in Santiago's dream adds a surreal and unusual element. Santiago's dream diverges from a representation of reality and instead conveys a fantastical realm where animals speak, indicating a deep connection with nature or hinting at a deeper symbolic meaning within the narrative context of the book.