This Kicker comes from Slipgate, and goes with the episode "Sick Day."
Disclaimer: All characters portrayed here are not owned by any of the writers…
Kicker #28
Episode #233: Sick Day
"No way, KP!" Ron cried.
"Face it, Ron. The Stoppable Fortress of Immunity is, well, stoppable." Kim chuckled at her statement.
"Oh, puns. I'm not feeling 100% here KP." Ron feebly defended.
Jim and Tim happened to be passing by with Kim's mom to head out for some clothes shopping. "Did Ron say he had a Fortress of Immunity?" Jim asked.
"Yup!" Kim replied, an amused look on the face she directed at Ron.
"But wasn't he sick along with the rest of us?" Tim asked.
"That's why it's so funny. There is no Stoppable Fortress of Immunity. It's a big joke." Kim replied, handing her best friend a fresh tissue.
"Nah-uh, Kim. You're forgetting a crucial fact here." Ron huffed.
"And what's that?" Kim inquired, grinning.
"All of you were sick, and I didn't get sick at all. I handled Operation Ray X when you couldn't move, Kim! Me! Ron Stoppable!" Ron declared, his voice rising as he went along.
He blew his nose, then continued, "I didn't get sick until Shego with her radioactive thing going on sprayed her illin' on me and got me sick. Normal human disease wouldn't have affected me! I call foul! I call foul!"