After watching BFMBA 9, I had a pretty cool idea for Red Slime. In BFMBA 10, he would still be empty until the elimination end , and after he (hopefully) survives the elimination, on of the team members from "QUACK" would go to refill him with a machine. And this will be during the challenge. Unfortunately, the machine will be out of Red Slime, so the team member that left decides to choose a different colors. So Red Slime, now known as Blue Slime, will revel himself at the end of the episode, and will stay this way until near the end of the season.
Sorry if there are errors in the writing.