Complex sentence: One of her only unique features is her odango hairstyle and a running gag is that her lack of presence gives her the ability to become invisible, accompanied by the sound "Akkari ~ n!".
Split into simpler sentences: One of her only unique features is her odango hairstyle. A running joke is that Akari's lack of presence gives her the ability to become invisible, accompanied by the sound "Akkari ~ n!".