Apoo's music devil fruit, the Oto Oto no mi, was criminally underrated and underexploited by Oda. Here are several powers and techniques I imagine for it:
- Concerto in Tears Minor: Apoo turns his arm into a violin to produce a sad melancholic music that causes the people to uncontrollably bust into tears and cry rivers of tears.
- Pied Piper: Apoo turns both of his arms into a pipe to play a serenade that allows him to control various animals around him. A technique he developped to subdue the boars he faced on his first island in the New World.
- La Sampa: Apoo creates maracas that cause the people hearing to be shaken as if they were in a giant hand and shaken by it.
- Kalachnikov Roll: Apoo turns his knees into snare rolls, which he drums with the enemies being pierced multiple times as if they had been hit by gatling gun fire.
- Electrik Symphony: Apoo turns his right arm into an electric guitar, which causes the foes who listen to it to be struck by lightning and electrocuted.
- Bermude Triangle: Apoo turns one of his hands into a musical triangle, which he softly hits with a beater, ironically causing devastating vibrations and either a shockwave or an earthquake that devastate everything within Apoo's music range.
- Diapason: Similar to the triangle technique, Apoo turn his hand into a tuning fork, using it to hit his enemies, weapons or buildings. The target have very powerful vibrations that go through him that can cause grievous internal injuries or even death on a living being, cause a weapon to shatter, and buildings to crumble to pieces.