Morusque is a musician robot sitting on the floor with a guitar down and to the left where you first meet the robots in Chapter 4: "The Slums". There are 8 total music sheets scattered throughout the slums in this chapter, so you must collect them all and bring them to Morusque. You can choose to bring them one by one or all in one sitting, but you will still need to wait for Morusque to play each song until the very end before being able to deliver the next music sheet. Alternatively, you can restart the last checkpoint immediately after delivering one music sheet if you don't want to listen to the whole song. This will speed up the process, as you'll spawn right in front of Morusque again and you'll be able to deliver the next sheet. Thanks to MohandGamer7 for this information.

In any case, as soon as you deliver the eighth music sheet and receive the badge, the trophy will pop.


This trophy is unavoidable if you're going for all badges anyway, so see  I Remember! for a video guide of all collectibles including the 8 music sheets in Chapter 4.