First, a big pot—stockpot size, at least 10 quarts—with a tight lid. You’ll also need a steamer basket (or a colander that fits) and crab seasoning like Old Bay or J.O. #2. Oh, and gloves? Please wear gloves. Your future self will thank you when you’re not picking shell splinters out of your palm.
Bonus: a pair of tongs with a long reach. Those claws can snap, and I mean snap. Trust me, I learned the hard way when one grabbed the tongs and tried to wrestle them away. It was hilarious—until it wasn’t.