Red Coins are a special kind of collectible item in Mushroom Kingdom Fusion. Unlike regular coins, red coins do not appear in every stage, only appearing in select stages throughout the game. There are always a total of 8 red coins in any given level, each one disguised as an ordinary coin, albeit with a slight red tint to give it away. Collecting red coins does not add to the player's coin total; instead, if all eight red coins in a stage are collected, it unlocks a special bonus, usually located at the end of the level. The bonus prize is indicated by a ring of red flowers and can be nearly anything such as items (rupees, powerups, 1-ups) or even non-collectable rewards (blocks, platforms, or keys). It can even consist of multiple different items.
And unlike normal collectible objects, the number of red coins collected in a level can be temporarily saved by hitting a level checkpoint. If the player then dies and re-enters the level, all red coins collected up to the checkpoint will still be in the player's possession and will be absent from where they were found. If the level is completed, however, or if the player dies and then enters a different level, then their red coin count will drop back to zero.