Combine 10 cups water, beer, Zatarain's Crawfish, Shrimp & Crab Boil, hot sauce, onion, lemon, garlic and bay leaf in a large stockpot or 9qt Dutch oven over medium heat. Bring to a boil; reduce heat and simmer, covered, until flavors have blended, about 10 minutes.
Stir in potatoes; reduce heat and simmer for 10 minutes.
Stir in corn and sausage; reduce heat and simmer until potatoes are just tender, about 10 minutes.
Stir in shrimp and cook, stirring occasionally, until pink and cooked through, about 4-5 minutes; drain well.
Serve immediately with butter mixture.
for the butter mixture
In a small saucepan over medium heat, combine butter, hot sauce and Old Bay seasoning. Bring to a boil; reduce heat and simmer, stirring occasionally, until fragrant, about 1-2 minutes.