Mr. Fa-Sol-La-Si is an S-grade pet released on April 10, 2015, along with Mint Choco Cookie and his other combination pet, Ms. Do-Re-Mi. The pet would generate Royal Blast Dash Coins, which give 100 coins and a Blast Jelly boost combined.
His Power+ effect is called Serenade of Love, which creates 5 Mini Energy Potions, altogether worth 10 Energy, and heart-shaped rings of Bear Jellies. Despite the game stating that owning him and Ms. Do-Re-Mi will cause their Power+ effect to only occur once per run, players have noted that the Power+ effect can occur twice, one for each pet owned. It is unknown why this occurs.
In the Wrath of the Dragon season, the Power+ effect can be activated without owning Ms. Do-Re-Mi. It is unclear as to why it happens.
He is known to be the cranky orchestra director who spares no biting criticism if a performance is not up to his standards, but no one can question his skill and innate sensitivity for music. He was the one to discover Mint Choco Cookie's talent and has been his advisor since they first met. While he used to be able to give ground-shaking performances, he is now conducting his orchestra.
Since the Season 5 update, the 'glitch' that causes the Power+ effect to occur twice in a run has been fixed. However, players have recently observed that this glitch is working again, and players are now able to obtain up to 4 Power+ effects per run.
Shortly with the release of Lime Cookie and Mr. Limeguard, there was another bug with Mr. Fa-Sol-La-Si Power+: he would never show up at all while Ms. Do-Re-Mi would show up three times each for the main Cookie and relay Cookie. This has since been fixed.
Currently in the LINE version, his Power+ works only when you obtained both pets. However, the effect can still be triggered twice per cookie, implying that the glitch has not been fixed yet. Also, the bear jellies are half-transparent, allowing the player to see part of the background.
Since the Wrath of the Dragon season, his combi bonus with Mint Choco increased from 10% to 12%.