In a slow cooker, combine the drained corn, softened cream cheese, sour cream, and shredded cheddar cheese.
Add the diced green onions, diced red bell pepper, garlic powder, chili powder, salt, black pepper, and cayenne pepper (if using). Stir until all ingredients are well mixed.
Cover the slow cooker and cook on low for 2 to 3 hours, stirring occasionally, until the dip is hot and the cheese is melted.
Once cooked, stir the dip well and serve warm with tortilla chips, crackers, or fresh vegetables.