Watch this video. When the actual headbanging starts at 0:45, you're pretty much guaranteed to burst out laughing.
The very idea of BABYMETAL. Extremely adorable idol music mixed with brutal and heavy-as-fuck, face-melting metal.
Let's just say a first time listener is going to have at least one Mood Whiplash moment, with the only appropriate response as laughter. Regular fans are used to these moments however, embracing it as a part of their sound.
The song Gimmie Chocolate!!!, literally a song to metal brutality...and it's about wanting candy.
The dubstep section of Uki Uki Midnight when one realizes it's a dubstep remix of the alphabet song.