Talk about adaptation. You can resist this sleepy song but be warned: you're putting Jigglypuff's life in danger if you do. It will continue to sing until either you fall asleep or it runs out of air.

Jigglypuff, while it can't apply damage with its Sing attack can apply Asleep on each turn with just one Energy attached, while Wigglytuff has Sleepy Song, an attack that deals 80 damage per turn ...