A mild illness that comes very soon after another mild illness. For example, when you have a flu and about a week before you had strep throat. The reason it's called sudden death is because it's the second round of your illness problems, as it were, and also it makes a morbid pun.
She had a sudden death illness that day, and she was sort of bummed, because that day she'd missed a big potluck at the community center.
The greatest and most powerful weapon in the multiverse, capable of wiping out an quintillions of ymas in seconds
Hey Brendan did you hear that billy, yeah that really cool one in year 9. So apparently he absolutely annihilated that yma girl with his patented Billy’s anti-yma extra ultra magnum quantum laser death ray pulveriser of awsomeness