Before you can get to the Grate Guy Casino you need the Bright Card to enter. You can get the Bright Card anytime after beating the Grate Guy and Knife guy in the boss fight. Go back to Booster's Tower after that fight and climb the tower until you see the Knife Guy juggling.
Talk to him and play his juggling guessing game. Guess which hand he has the yellow ball in 12 times in a row and you will be rewarded with the Bright Card. Now go to Bean Valley. There will be a screen with 5 pipes. Go down the pipe closest to the save point.
In that pipe there will be a secret entrance to the Grate Guy Casino. You can find that entrance by going to the corner with the Chomp and jumping 3 times. Then as long as you have the Bright Card you will have no problem getting inside. Inside you can play a number of games including slots and blackjack.
The odds of winning any regular coins or frog coins in the Grate Guy Casino are highly against you like any normal casino. The only worth wild item at the Grate Guy Casino is the Star Egg which is a battle item that does 100 damage to every opponent. It can be used more than once which makes it more useful than any bombs you can get.
You can obtain the Star Egg in the Grate Guy Casino by winning 100 juggling guessing games against Knife Guy. You don't have to win 100 in a row just guess 100 times correctly without leaving the casino. If you leave the casino the guessing game count resets and you have to start over. If you made it this far congratulations for finding the Grate Guy Casino and obtaining the Star Egg.
Matthew Corgan is the author of http://www.originalnintendo.net and http://nintendowee.blogspot.com
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