During Tibia's 15th Anniversary you could loot Simple Fanfare and other instruments from Groupies.
Once you have it, go to Mercutio's Band here.
Then, use a Chameleon Rune on the fanfare, and play some to the band.
If you play the simple fanfare without the proper form you'll get a white message: "This might be even better with the right outfit."
When you get transformed: "Good idea. Might sound and look awesome in Mercutio's band!"
After playing transformed: "What a great addition to the band! The piano man might reward you."
Say hi and enjoy your reward (blue surprise bag).
- This item is not dropped by any creatures.