Please ignore my previous theory about the challenge being shell collecting, I just rewatched it(are you honestly surprised) and I saw this flash for a split second, so I tried several times to pause it just in time, and I eventually did and screen shoted it:

The challenges is bucket brigade!!!!!!!! Also, I forgot to mention in my predictions/theory's that I think the armless alliance will be split in half next episode. Obviously baseball will still be friends with both of them, but nickel and Suitcase have been having a bad time with each other lately(yes, I had to include the undertale reference) and I think Suitcase will quit the alliance and hang around with Balloon for a while.
Anyway guys, that's all for now, thanks for reading, I hope you enjoyed, and I will see you in the next chapter, bye 😜