My wife mentioned this to me today.  Found an article on it on Business Insider Nordic.  Turns out CostCo is sold out, but you can get it on Amazon, too.

Costco is selling a 27-pound tub of mac and cheese that lasts 20 years

• Costco is selling a giant tub of macaroni and cheese for $89.99.
• The nearly 27-pound tub contains 180 servings and can last for 20 years.
• Customers reviewing the tub on Costco’s website say that despite its long shelf life, it tastes delicious.