How does the secondary effect of the Heat Metal spell work?

Question

The heat metal spell description states:

If a creature is holding or wearing the object and takes the damage from it, the creature must succeed on a Constitution saving throw or drop the object if it can. If it doesn't drop the object, it has disadvantage on attack rolls and ability checks until the start of your next turn...

I am unsure how this disadvantage mechanic functions as a whole. When do you suffer from it and in what ways (if any) can you end it?

For example:
What happens if you fail the save but cannot drop the object? Does dropping the object later, on your turn, do anything?
What happens if you succeed on the save? Does dropping the object later, on your turn, do anything?

I would like it to be assumed that you cannot willingly drop a weapon when it is not your own turn; however, heat metal can still force you to drop the weapon.

I would also like it to be assumed that the saving throw is not optional.

Answer 1

Building on my answer here and the discussion in the comments, I think it's really up to the DM. The spell is written too ambiguously to rely on RAW. I can see it interpreted t̶h̶r̶e̶e four ways:

1. There is no disadvantage if the Constitution save is passed

This was my first interpretation when I saw the spell. The Constitution save determines whether the creature is required to drop it and the disadvantage is a consequence of not being able to fulfill that requirement, rather than a consequence of not dropping it. As previously stated (in case the other question is closed or deleted):

The spell refers to dropping it anytime the damage occurs and the Constitution saving throw is failed (emphasis added):

Choose a manufactured metal object, such as a metal weapon or a suit of heavy or medium metal armor, that you can see within range. You cause the object to glow red-hot. Any creature in physical contact with the object takes 2d8 fire damage when you cast the spell. Until the spell ends, you can use a bonus action on each of your subsequent turns to cause this damage again.

If a creature is holding or wearing the object and takes the damage from it, the creature must succeed on a Constitution saving throw or drop the object if it can. If it doesn't drop the object, it has disadvantage on attack rolls and ability checks until the start of your next turn.

As I understand it, if the Constitution save is failed, the creature must drop the object if possible. If the object cannot be dropped, then disadvantage comes into play. If the save is passed, the creature does not have to drop the object and does not suffer disadvantage.

This would be akin to the creature steeling itself to the heat and not being affected by it all.

2. There is disadvantage only if it's not dropped at anytime, regardless of the save

Per one interpretation, the spell only says "If it doesn't drop the object", so it could be valid that any dropping of the object eliminates disadvantage. This would be akin to the object still being too hot to handle effectively, regardless of whether the creature steeled itself to the heat (i.e., the creature can grip it, but it's still hot enough to cause distracting pain).

3. There is disadvantage only if it's not dropped immediately when failing the save

The third interpretation could be that the "drop" in the phrase "If it doesn't drop the object" means the drop from failing the save and only that drop. Even if the creature drops the item, the pain may linger for the turn, causing the disadvantage.

4. There is disadvantage only if it's not dropped immediately regardless of the save

This one feels the least likely to me if the answer to the linked question holds true, as a creature with a successful Constitution save would always suffer disadvantage (because it can't drop the item) while one that fails would have the opportunity to drop it. However it would be possible that the phrase "the creature must succeed on a Constitution saving throw or drop the object if it can" can be interpreted as "the creature must succeed on a Constitution saving throw or must drop the object if it can", which is another can of worms because then is the creature allowed to make a voluntary drop when it's not its turn?

Answer 2

Here is the sequence:

1. Take damage on the spellcaster's turn
2. Roll your saving throw:
   1. If you pass, there are no further effects this round. Otherwise the saving throw does nothing.
   2. If you fail, you must immediately drop the object if you are able to; if you do, there are no further effects this round.
   3. If you fail and are unable to drop the object, you suffer disadvantage as stated until the start of the spellcaster's next turn. No matter what you do with the object after this, the disadvantage lasts until then.
3. What you do with the object on your following turn (pick it up, drop it, etc.) is irrelevant.

Why this is not ambiguous

It isn't your turn. Because it isn't your turn you can't do anything other than what the spell says you do. In particular, you can't interact with the object voluntarily, by dropping it for example.

The phrase "succeed on a Constitution saving throw or drop the object if it can" means that if you succeed on the saving throw you don't drop the object and if you fail you must drop it "if you can". The next sentence is dealing with the "if you can" part of the previous sentence and lays out the consequences if you can't. Top read it any other way gives the saving throw no work to do - i.e. if you read it any other way it makes no difference if you pass or fail the save.

With that context, the sequence outlined above is the only sensible reading.

Answer 3

https://www.sageadvice.eu/2014/11/17/heat-metal/

@DeadOnToilet Rules question on the spell Heat Metal. If I’m wearing plate armor and make the saving throw, do I still have disadvantage? You have disadvantage while you're wearing the heated metal. Your best bet is to break the concentration of the spellcaster.

— Jeremy Crawford (@JeremyECrawford) November 17, 2014 (Wizards of the coast lead rules designer)

So in steps
1 take damage from the fire
2 make a con save - fail and you must drop the object (if it is possible to drop it).
3 if you are still holding the object (or if you are wearing it) you now have disadvantage.