Mood Stones are magical stones with the power to change the emotions to the emotion the stones represent. there are six colors for each mood, which are blue for sadness, white for joy, yellow for fear, pink for love, green for envy, and purple for hoity-toity respectively.
In the episode The Flawed Couple
Abis Mal introduces the mood stones and tests them out on himself and Mechanicles combines them with his robot bugs after one of them used the yellow stone to frighten away the thugs that are trying to pulverize them. They tried to use them on Aladdin and his friends but Aladdin resists the spell and got his friends back to normal.
