I think the Doku Doku No Mi is the most threatening. It can even in the hands of somebody who we didn't see use Haki allow for said person to take out a soon to be Emperor. It also can enter a gas mode and produce gases that are poisonous which makes it faaaar scarier in my opinion.

Doku Doku for sure…

Plus it causes extreme pain

Would you rather die a slow painful death or a quick brutal one in which you melt to ashes

I would prefer the magma cuz while that's instant pain into death at least it's fast

Luffy suffered for like 4 weeks (get it? time > manga time... funny)

Idk I think magma is more threatening even if poison would be more painful death

When I say threating I moreso mean. Let's say you give one of these fruits to like Don Krieg, which one makes him more dangerous. He is still weak on his own but thesw fruits make him a threat to some of the highest ups in the world anyway. Which would make somebody more threatening

I honestly think Magu Magu is more threatning. Don't get me wrong, the Doku Doku is hella dangerous and almost ended Luffy and Blackbeard early, but the thing about the Doku Doku is that you actually have a cure for the poison while the Magu Magu is a much different story. Maybe when Magellan is in that red poison form, the cure is nine times outta ten useless, but the Magu Magu just seems more dangerous in a way since you don't have a cure for it.

A fair point, but also consider the Doku Doku can work through gases it makes too which I would argue makes it more scary as well as it isn't just something relatively easy to dodge like a Liquid

Magu could be way morre threatening than we saw due to magma being below the tectonic plates meaning it could cause a similar effect to the gura gura no mi

The doku doku fruit is a slow and painful death