User blog comment:Srebak/Who came the closest to ending Luffy?/@comment-10543621-20141102232339

I'd say Crocodile and Magellan, because those were two adversaries that Luffy was completely defeated by, and left for dead, with no way to survive if it weren't for someone saving their lives.

Especially for Crocodile, he had no allies nearby. The fact that Robin decided to save him was completely unexpected. Magellan, at least he had a loyal friend close by him who literally went all out. So I'd say Crocodile.