It’s not burning the target on their turn, it’s actively being triggered by the caster, basically just an attack action or Spiritual Weapon trigger, and those can “stack” with no problem. Remember that heat metal takes concentration and a spell slot.
Can you twin heat metal?
No, Twinned Spell only works with spells targeting creatures 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. So, unfortunately, RAW, Twinned Spell will not work with heat metal (as you suspected).
Can you cast heat metal on a warforged?
You can’t target a warforged with heat metal, because warforged are creatures and heat metal only effects objects.
Does heat damage metal fire?
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.
What happens when you use the heat metal spell?
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.
What happens when you cast heat metal at a higher level?
If it doesn’t drop the object, it has disadvantage on Attack Rolls and Ability Checks until the start of your next turn. At Higher Levels: When you cast this spell using a spell slot of 3rd Level or higher, the damage increases by 1d8 for each slot above 2nd.
How much fire damage does heat metal do?
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.
How does the secondary effect of the heat metal work?
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
