While in the connection room to the Drablands, if you do a Pegasus dash (L1/R1) and the walls or pillars, a ball will fall from the ceiling. If you slash it, it will pop up in the air and you can keep hitting it to keep it in the air. Depending on how long you keep it up, you will get some bonus rupees.
Cacto Costume
Complete Bonus Challenges: Woodland and Riverside.
Normally, the only way to get a Friend Token is by playing local multiplayer with others, and even then, you can only earn one per person. However, there is a way to buy them. Once you've defeated all of the bosses in the game and seen the ending, go talk to the shop owner in the middle of town. He will announce that he has started selling Friend Tokens as part of his normal rotation. They won't be available every day, but when they are, they will cost 2,000 Rupees a piece. This will make earning some of the costumes in the game much easier.
Receive Gold-Rank Materials from the King
After clearing all sixteen Challenges in a World (the normal run plus all three Challenges of each of the four Levels) go and talk to the King. He will give you a Gold Rank Material for that World which can otherwise only be obtained from the Colosseum. It doesn't matter if the Challenges were cleared in Multiplayer or Solo Mode, as long as all sixteen Triangles are lit up on the Board. You can only receive 1 of each Material from the King.
Ball Pop Game...