If you’re a casino player, you’ve likely seen jackpot versions of your favorite games with staggeringly huge prizes. In fact, the biggest jackpot ever won on a slot machine was $39.7 million! And while you’ve probably been tempted to spin them, there’s a few things you should know before you do.

The first thing you should know is that when you win a jackpot, you’re not going to get the money right away. A casino worker will rush over and ask for identification. This is because winning a jackpot sends a signal back to the monitoring room, and the casino is required by law to verify that it’s a legitimate winner before handing over any money. That means you’ll need a government-issued ID, and you won’t be able to cash the check until you have it on hand.

Another important thing to keep in mind is that the IRS gets a cut of your jackpot. You’ll have to file a W-2G, which is an IRS form designed specifically for gambling winnings. Depending on your tax status, you might have to pay federal and state taxes as well.

A casino jackpot is a top prize for specific casino games that continues to rise until a player wins it. These are typically found in video poker machines and slot machines, and they increase by a small percentage of each wager placed on the game. These top prizes can be enormous and are often advertised boldly on the machine. Some progressive jackpots are part of larger networks that include casinos in multiple cities or states, while others are on individual machines at one specific casino.