Toad Stars (also known as Power Toads, and formerly as Power Stars) are objects with magical power that allow whoever has them to have lots of different powers.
During Toad-megeddon, Mario attempted to gather all of the Toad Stars and stop Toad with them. Toad found out about this plan since he had eyes on Mario's face. So before Mario could gather the stars and defeat Toad, Toad swapped them out for decoys. They were enough to fool Mario.
After Mario was brainwashed, Toad put all the Toad Stars back and then collected them during Super Releasio 64 as a challenge.
Toad Stars are randomly scattered throughout Toad Hell. Some of them are just sitting in random spots, waiting to be collected. Some of them are hidden, and need to be unhidden in order to be collected. Some of them appear after solving certain puzzles. Some appear after getting 100 Toad Coins.
A Toad Star appears in Toad's Fun Releasio Adventure after completing level 3. Collecting it takes the player to the next level.
Toad Stars have appeared in the following games: