Soo... the depths music and effects started randomly playing on my Spearmaster campaign... is this normal?

https://preview.redd.it/ae248qsxb8pe1.png?width=1780&format=png&auto=webp&s=836d1e75365c076b694c3efc165458db2770062c

Is my spearmaster entering some sort of trance like state or something? This is... weird