For me, it's the Stone Talus. You literally have to hit the gem container on it's body multiple times until it dies, preferably with a ancient arrow or a iron sledgehammer.

That's it. That's all that you have to do

Um... I dunno. Maybe.... uh.... I don’t know. One of the blights from BoTW was easy, I think. Let me think on this

I’d have to say....... imdon’t remember, I think one of the -blights