Helter Skelter mashup is my preferred one over originals: https://www.youtube.com/watch?v=9VhW67Ya8jo

Many WaxAudio mashups are top-tier, such as: Bee Gees + ACDC: https://www.youtube.com/watch?v=OrlWWrSwaB8 Stevie Wonder + Metallica: https://www.youtube.com/watch?v=KyvxHL5hLfE