In the bowl of a food processor, combine the cheddar cheese, cream cheese, garlic powder, onion powder, Worcestershire, paprika, mayonnaise and pepper. Process until smooth, about 1 minute, stopping the machine to scrape down the sides of the bowl as needed.
Place the cheese mixture on a large piece of plastic wrap. Gather the edges of the plastic wrap and pull up, twisting it around the cheese to form a ball. Place the cheese ball on a plate and refrigerate until firm, about 4 hours.
(If you’re not satisfied with the shape of the cheese ball after it has chilled, let it soften slightly at room temperature and then reshape. Refrigerate the ball for 1 hour more before rolling in chia seeds.)
When the cheese ball is firm, remove the plastic wrap. Place the chia seeds in a bowl and roll the cheese ball in the seeds until evenly coated. Transfer the cheese ball to a serving plate and let stand at room temperature for 20 minutes before serving. Serve with crackers. Serves 20.