Lunatic Bass is one of two weapons that are a direct upgrade to the Ax Bass as a super rare, which still provides better damage but also pierce to Marceline. Jake and Tuxedo Jake don't care for damage and pierce.
Fire Guitar is better for a more support focused Marceline, as the pierce buff isn't useful by the time players have rare trinkets and 4-5 starred characters. Penguin Shell can be considered as a hybrid of the two, with weaker stats in each build.
Provided the player can get it early enough, it provides a good amount of pierce for low star characters to be effective.
