Brain teasers are puzzles or riddles that challenge the mind and require creative thinking, logic, and problem-solving skills to solve. They often involve wordplay, lateral thinking, or mathematical reasoning and are designed to provoke mental engagement. Brain teasers can vary in complexity and may have a straightforward answer or require more elaborate reasoning to arrive at a solution. They are commonly used as a form of entertainment, educational tool, or mental exercise to enhance cognitive abilities and critical thinking.