Does a Small race do extra damage when enlarged by the Enlarge/Reduce spell?

Question

Me and a friend were discussing gnome barbarians, and the fact that Small creatures have disadvantage on an attack when using a weapon with the heavy property. I brought up that the Enlarge/Reduce spell would negate this disadvantage by making the gnome have a size of Medium temporarily.

Though, the Enlarge/Reduce spell also causes creatures to do 1d4 extra damage with weapons they use. If a gnome/kobold/halfling/goblin were to hold a greatsword, and have a wizard enlarge them, it appears that, not only would the disadvantage imposed by being a Small race be removed, but they would also do 1d4 damage more than any normally Medium character using the weapon. This makes no sense to me, though; am I reading everything correctly?

Does a Small race do extra damage when enlarged by the Enlarge/Reduce spell?

Answer 1

The enlarged player would attack with extra damage

The Heavy property for a weapon reads (emphasis mine):

Creatures that are Small or Tiny have disadvantage on attack rolls with heavy weapons. A heavy weapon's size and bulk make it too large for a Small or Tiny creature to use effectively.

As mentioned in other answers, the enlarge section of Enlarge/Reduce reads (emphasis mine):

The target’s size doubles in all dimensions, and its weight is multiplied by eight. This growth increases its size by one category—from Medium to Large, for example. If there isn’t enough room for the target to double its size, the creature or object attains the maximum possible size in the space available. Until the spell ends, the target also has advantage on Strength checks and Strength saving throws. The target’s weapons also grow to match its new size. While these weapons are enlarged, the target’s attacks with them deal 1d4 extra damage.

Under the effects of Enlarge/Reduce, the gnome would no longer be considered a small creature and so would not suffer disadvantage from the Heavy property, and RAW the enlarged weapon would deal an extra 1d4 damage.

Answer 2

I see 2 options

My preferred option: You would gain the +1d4, but also retain the disadvantage

You enlarge to medium size, but the greatsword would enlarge to large size and thus still give disadvantage for wielding a weapon one size too large.

A creature has disadvantage on attack rolls with a weapon that is sized for a larger attacker. You can rule that a weapon sized for an attacker two or more sizes larger is too big for the creature to use at all

DMG, Chapter 9, Section 11

I base this on the fact that the spell very likely doesn't account for people already wielding weapons not designed for them, because that is an edge case.

The rules generally don't handle edge cases very well at all, or more specifically does handle them by shifting the responsibility onto the DM.

Option 2: The weapon doesn't change at all

The target's weapons also grow to match its new size.

The weapon in this interpretation doesn't grow at all, so doesn't cause the extra damage.

Answer 3

The weapon grows with you and that is what does the extra damage.

Enlarge portion of the spell emphasis mine

Enlarge. The target's size doubles in all dimensions, and its weight is multiplied by eight. This growth increases its size by one category - from Medium to Large, for example. If there isn't enough room for the target to double its size, the creature or object attains the maximum possible size in the space available. Until the spell ends, the target also has advantage on Strength Checks and Strength Saving Throws. The target's Weapons also grow to match its new size. While these Weapons are enlarged, the target's Attack with them deal 1d4 extra damage.

Your size category increases and your weapon size does too. The extra damage explicitly comes from the enlarged weapons so I would rule that either you could hold the weapon while getting enlarged or drop it then pick it up so it didn't change in size.

If the weapon gets bigger you get the damage and still have disadvantage, if not you lose disadvantage and the damage.