Fun facts:
That Jigglypuff which always singed people to death appeared last in the 39th episode of Hoenn’s anime. But in the 138th episode of it, there was this guy who was trying to catch another Jigglypuff which also knew Sing. He happened to choose a Loudred to do the job, because of Soundproof's effect.

So what happened to that jigglypuff anyway? I remember how it used to draw scribbles in everyone's faces while they were asleep because its song.