What is the advantage of casting the Light cantrip on an object an enemy is wearing or holding?

Question

The cantrip light (PHB, p. 255) says that it casts a "bright light". It also states that:

If you target an object held or worn by a hostile creature, that creature must succeed on a Dexterity saving throw to avoid the spell.

Why would there be specific text directly dealing with casting it on an enemy unless there was some benefit? I was thinking that the spell could either;

1. temporarily cause the blinded condition

   or

2. have a similar effect to the Help action and allow an ally to gain advantage on their next attack roll against that enemy.

Either way, I would assume a glowing object would at least give my allies a bonus to see the enemy and make it near-impossible for the enemy to hide while holding or wearing a "bright light."

Answer 1

This is merely giving an unwilling creature a chance to not be affected by a spell.

It does not do anything special by default.

However, for some creatures, it may end up providing disadvantage. Many creatures who are native to dark areas do have disadvantage when they are in bright light.

It may also help if you are trying to remain hidden. If you are in the dark, and your enemy is in the light, then he is visible and you are not.

Again, this is trying to prevent this spell from being overpowered. All it's doing is providing the enemy with an opportunity to avoid the effects (being lit up like a Christmas tree). There is no default benefit here.

Answer 2

Either way, I would assume a glowing object would at least give my allies a bonus to see the enemy and make it near impossible for the enemy to hide while holding or wearing a "bright light."

This is exactly it. You can see the target - even if you're in the dark. This is why Drow in groups with non-Drow tend to open with Faerie Fire (which is a better option for highlighting targets without revealing your own position). All it takes is one caster with darkvision / low-light vision to reveal the enemy - and all his friends standing too close.

Answer 3

AS has been mentioned already the spell itself has no negative impact on the enemy per se BUT it can be useful in some cases. Talking here mostly about RPG aspects as I'm not too familiar with the dnd5e rules themselves

• If you want to flee inside a cave system the enemy and want to know WHERE he is at it is quite nice (and which orc would remove his plate mail just because it shows the enemy where he is at). Also in case of things with no eyes at all (only tremorsense,...) they wouldnt get it HOW you always know where they are at.
• If the enemy is invisible and you manage to hit him......it could be reducing the effect of invisibilty (ok there is nothing there but there is some glowing sheen.....strike the glowing thing there). Here I'm not sure how invisibility functions in 5th could be that it "absorbs" the light.
• You could use light to "mark" targets for archers that are too far to shout at "target this one who is holding the spear of destruction"
• For more normal chars ... thus those without low light and infravision it would bereft them of their night vision leading to them not seeing well anymore in the dark (outside of the area of shine). A sudden light could also be quite dazzling to them (depends on the gm though).
• Then there are those who are vulnerable to light like drows in most systems,... you could make sure they are blinded,... for a while with light. As the drow would have to choose if he wants to see nothing or strike you with his/her bare hands instead of a sword.
• As mentioned in a comment: Cast it on an animal (as that would be unwilling) so that it runs around and distracts guards or superstitious beings.

Answer 4

By default nothing, but depending on the case a DM might allow some benefits.

Could be a common solution is to not lose an opponent.

A rogue will find it difficult to hide in combat. A Shadow dancer, will be not able to jump through shadows (possibly). An enemy about to flee will find it harder to hide even in the crowd when he is a firefly.

Light is a utility spell and can be used in many imaginative ways. A DM might give blindness or disadvantage for a round if cast on a helmet.

The save is actually to test if you can cast the spell to an unwilling target. In 3.5 you could do the same with touch attack instead.

In case of invisibility though...

Items dropped or put down by an invisible creature become visible; items picked up disappear if tucked into the clothing or pouches worn by the creature. Light, however, never becomes invisible, although a source of light can become so (thus, the effect is that of a light with no visible source). Any part of an item that the subject carries but that extends more than 10 feet from it becomes visible.

So imagine that, you cast the light spell on a cloak of invisibility, the target becomes invisible. While he probably gets the invisibility bonuses, you can still target him with area effects and I would allow (as DM), to attack the invisible target with melee and ranged attacks but with a disadvantage.

Answer 5

The other posters are correct, but I would add, if you cast light on yourself, or other inanimate (and not worn) object, no saving throw is required, but, the enemy can move outside the spell's radius. By risking the saving throw, you also ensure the light moves with the target.

Answer 6

Light has detrimental effects if cast on some items. For example, if you cast light on a Robe of Many Eyes then it blinds the wearer.

Answer 7

There are all good answers. I'll try to improve the especter: one can always think in some new way to use the spell, principally in no battle situations.

The bards or even some druids can be famous for conjuring spells in a conceiled or even "apparently natural" way, it could light some equipment of a gateguard for instance, oughting that its power has let it curse the so equipment, and that the light is only reaction of its tremendous grasp over reality, the guard then... well, would let the strange powerful figure pass or chop its head off.

:)

Mechanically, this situation could gave the bard/druid a tremendows buff on a bluff shot against a simpleton guard. I would even consider a automatic success if a player came with this little trick, hailing the role play.

If you like the idea of "aparenttly natural spells", I recommend read the Bernard Cornwell's trilogy of king Arthur, you can have some pretty ideas there.