Heat Metal provides the ability to render a foe helpless on the battlefield by creating searing hot fire damage to any metal they hold or wear. The spell has seen a major resurgence and has become a staple for some classes in 5e.
The rules for Heat Metal can be found in the Players Handbook on page 250.
Heat Metal 5e
Transmutation 2nd Level
Casting Time: 1 Action
Range: 60 Feet
Components: V, S M (Apiece of iron and a flame)
Duration: 1 Minute (Concentration)
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 a 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 level above 2nd.
The rules for Heat Metal reveal how devastating this spell can be. The ability to deal damage round after round to any creature wearing metal armor is pretty significant, depending on the situation. It is easy to see why Heat Metal has become more popular with 5e.
Does Heat Metal Work on Warforged?
This is a great example of the clarity provided by the spell description in 5e. The spell description for Heat Metal specifies “choosing a manufactured metal object.” Since Warforged is creatures and not objects, they cannot be targeted by Heat Metal.
For further clarification, the second section of the description specifies the object as being held or worn. Warforged is made from metal and is neither wearing nor holding that metal. That is not to say a metal object being held by a Warforged could not be targeted. It is entirely possible to target a metal object held or worn by a Warforged.
Can Wizards Learn Heat Metal?
The Heat Metal spell is only available to the Artificer, Bard, and Druid classes as a standard spell selection. The Forge Cleric also has access to the spell. Many of the spells available in 5e overlap with the Wizard’s list in some way, but Heat Metal is one of those exceptions.
The classes that have Heat Metal available have lore that is a rough explanation. Artificers work with and manipulate metal through an alchemical process mixed with magic, so it makes sense as a class spell for them.
Druids are strongly opposed to almost all manufactured metal, so, again, the spell makes sense as a class spell. The Bard has the power,in theory, to manipulate materials through frequency so they could create the same effect as the other two, although in a different way.
Does Heat Metal Work on Magic Items?
Heat Metal, according to the spell description, will work on magic items. As mentioned earlier, if there is nothing in the spell that prevents it from working, then it does. There are specific rules for magic item resilience in the DMG on page 141.
These rules describe that all magic items should have resistance to all damage. This is geared towards destroying the item. However, it could be applied to resisting Heat Metal’s damage as magic items are supposed to be far superior to mundane items.
Is Heat Metal Concentration?
Heat Metal is a concentration spell based on the spell description. It will last up to one minute, provided the concentration is not broken before the duration. There is not a save for the damage for the spell but rather to avoid dropping the object if the target can.
This line might be the most important in the description. A creature who is wearing metal armor is unable to drop the armor. This means they would be susceptible to all of the damage and the following rounds of damage if the caster chooses to deal subsequent damage.
The Heat Metal spell is one of the best Druid spells available. It has a strong lore and roleplay value to support using it. The spell itself does a significant amount of damage at a decent range. The ability to cast it higher levels is a huge benefit as well, allowing the spell to be useful at higher levels.
The only downside is the niche of only working on fabricated metal objects. This renders the spell relatively useless against non-armor-using monsters.