Bring a large pot of salted water to a boil and cook the rotini until al dente. Drain and rinse under cold water, then shake off excess water.

In a large mixing bowl, whisk together mayonnaise, sour cream, and ranch seasoning mix until smooth. Adjust with black pepper if needed.

Dice cucumber, halve cherry tomatoes, finely chop red onion, and crumble cooked bacon into small pieces.

Add cooled pasta to the bowl with dressing and fold gently until coated. Add tomatoes, cucumber, onion, cheese, corn, and bacon, then mix carefully.

Cover and refrigerate for at least one hour. Stir before serving, sprinkle with parsley, and adjust salt if needed.