Versus

Versus Damage
When a PC scores an advantage hit with a weapon attack who's damage type exploits the enemy's creature type (see below), it deals an additional die of versus damage as indicated, added after vulnerabilities are calculated.

Non-weapon spell attacks (and attacks from lit torches, acid vials, etc.) deal 'energy'  versus damage in the same way. A character may deal each versus die (slashing, piercing, bludgeoning and energy) only once per round.

A creature must have it's armour type (if any) exploited by versus damage in a round before it's creature type(s) can be exploited. Spell Armour is any spell that grants or improves an AC, and counts as an armour type.

Damage vs. Type

 * Slashing (+1d6) - Kith, Plant, Ooze, Aberration, Fey, Light Armour
 * Piercing (+1d6) - Beast, Dragon, Giant, Monstrosity, Medium Armour
 * Bludgeoning (+1d6) - Celestial, Construct, Elemental, Fiend, Undead, Heavy Armour
 * Energy (+1d6) - Phantom*, Spell Armour

Two-Weapon Fighting
When two-weapon fighting with weapons dealing the same damage type, you may deal an extra versus die of that type that round. The extra die may be dealt to the same creature if it has an additional exploitable type, or to a different creature with an exploitable type (you still need advantage on your attacks).

Edge-cases

 * Weapons dealing damage other than slashing, piercing or bludgeoning count as energy.
 * If an attack deals more than one damage type, choose only one to trigger versus damage.
 * Applying poison to a weapon does not cause it to deal energy versus damage.