Pour beer, vinegar, and water, and Old Bay in a pot over medium to high heat and cover.
When water reaches a rapid boil, add shrimp, cover again, and cook 2 minutes or until shrimp turn pink and just opaque.
Drain in colander and cover with a layer of ice to chill and stop cooking.
Cover with garlic and seasoning. Chill thoroughly in refrigerator until serving.
Serve with Cocktail Sauce.