Super simple and delicious. You need shrimp (in shell headless or not doesn’t matter), sausage (any non breakfast linked kind, cut into inch pieces), corn on the cob (cut into 3 or 4 inch pieces) , red potatoes, 6 lemons (halved), 6ish beers (bud light or something. Cheap and domestic), and crab boil. Fill a giant pot with water and beer. Add lemons and crab boil. Bring to a boil. Add the ingredients in this order and cook accordingly. Potato for 10 minutes then add the corn for 5 minutes then sausage for 5 minutes and then shrimp for 2 minutes tops. Traditionally it’s then poured onto a table covered with newspaper. Eat around said table.
Wha-? You never used Zatarains before? Oh my Lord, get yourself to the South. ETA: Ah, didn't realize gamecocks responded.
I've always taken "crab boil" to be the entire process/result, like "bbq", not a specific ingredient. Until this thread.