While you're gathering ingredients, scrub the red potatoes and cut them into 2-inch halves. Cut the king crab legs into 6-inch segments if not already done, and slice the celery into thick 1-inch chunks to prevent it from overcooking. Slice the sausage into 1-inch rounds and halve the lemons. Bring 24 cups of water to a rolling boil in a large stockpot (8+ quarts), then add 1/3 cup seafood seasoning and the smashed garlic cloves. Add the prepared potatoes and let them cook for 15 minutes—this gives them a head start since they take the longest to cook through.

While the potatoes cook, bring a second large pot of water to a boil with 1.5 teaspoons of seafood seasoning. Add the prepared king crab leg segments and let them cook for 10 minutes. I like to cook the crab separately because it prevents the broth from becoming too fishy and overwhelming the other ingredients. Drain the crab in a colander and set aside—it will be added back at the very end to warm through without overcooking.

After the potatoes have cooked for 15 minutes in the main pot, add the carrots, celery, and pearl onions. Let these cook for 10 minutes until they start to soften. Then add the sliced sausage and corn ears, and bring everything back to a boil for 5 minutes. The sausage will release its smoky, spicy flavors into the broth, seasoning all the vegetables and potatoes evenly.

Add the shrimp and the cooked crab legs from Step 2 to the main pot along with the lemon halves. Let everything simmer together for 2–3 minutes just until the shrimp turns pink and opaque—don't overcook or the shrimp will become rubbery and tough. Taste the broth and adjust seasoning if needed. For the best presentation, I like to serve this boil family-style in a large shallow bowl or on a bed of newspaper, letting everyone help themselves.