I recently came into a situation (in a DnD 4E game) where a player, knowing an invisible creature was somewhere nearby, wanted to take the light spell off of his staff and cast it on a handful of dirt, scattering it around the air to cling to the target and make him visible.

I let him do it because I like to encourage creative uses of spells, however I am not sure if the light spell should actually scatter into a bunch of smaller specks of light with each speck of dirt or if the source of light is more of a single point that should stay with only one speck of dirt.

I have not found anything yet which describes the behavior of the light spell on a scatter-able object, but I am not a very experienced DM either so I do not always know where to look to find this type of information. How should this have worked? Was this ok?

  • \$\begingroup\$ Would earth, luminous or otherwise, actually stick to a character? My characters prefer flour. \$\endgroup\$ Dec 13, 2013 at 15:43
  • \$\begingroup\$ They were underground I figure it is a little moist and at least some of it would cling \$\endgroup\$
    – user10064
    Dec 13, 2013 at 15:45
  • \$\begingroup\$ I edited the title to be specifically about how the Light spell works, since the rest of it isn't actually asking anything about invisibility. \$\endgroup\$ Dec 13, 2013 at 16:13

4 Answers 4


It makes all the dirt glow. Or, actually, it makes only one speck glow. See, the thing is that it's actually up to you, the DM. Let me explain...

So, there's a thing you have to know about D&D 4e: the designers didn't care about this stuff. They wrote a game that rigorously defined some parts of the powers rules (mostly what effect they have in combat), and then left the details of how the powers actually work in the game world's reality either vague or undefined. That was a deliberate design decision on their part: they wanted to get away from rules that had different interpretations during combat, but wanted the roleplaying, out-of-combat creative stuff to be almost completely un-defined by the rules.

This was a big change from how D&D had been written until 4e. Your intuition that the rules should cover this somewhere is reasonable and common, especially given how specific the game's rules are otherwise, and since most games are written like that. It will take a bit of a switch of perspective to start looking at the rules differently, but it's actually useful, the way the game splits the authority between itself and the DM.

So, the result of all this is that the game doesn't tell you how this works. It suggests a little bit in the description of the power, but the "fluff" description and the Effect description actually contradict each other – the fluff says it's "a bright light" and the Effect says that the target itself (presumably the whole target) sheds the light – again, because the designers didn't actually care about how the spell "really" works in the game world and didn't bother nailing this down.

Consequently, how this works is entirely up to you. That's a great freedom and a great burden: the game won't really help you out with deciding things like this, but on the plus side, it won't tell you that how you think it should work is wrong, either. Based on what you wrote in the question, it sounds like you personally like the "it all glows" interpretation. So, you being DM, and the game not actually caring about the answer, your interpretation is right in your game.


The dirt is an improvised weapon, so he would have to make an attack roll with a +0 proficiency against the square to hit with the handful, with a -5 for the target having total concealment if you don't consider the dirt as a close or area attack. (Check "Targeting What You Can't See" sidebar on PHB1 pg281). This is presuming that the largest clump of the dirt retains the spell and sticks to the target.

Also, Light says "one target or unoccupied square" so you could have him target the square they think the invisible character is in with the spell and optionally give you an implement based attack roll against 15 (10+concealment) to actually hit them. Success means the light hits the target and can thus move. Thank goodness it's an at will ability.

Edit: As far as how Light works on loose form objects, at my tables I would ultimately would force the player to pick a solid object or otherwise target the square. However, targeting any object that changes size does not change the base effect. It can only radiate from one point/square and emanate outward even if the object moves as per the effect of the ability.

Edit 2: After discussing with a 4e DM I know, he said he would make any object that expands stay lit the whole way, but diffuse the entire body it was cast on. IE if it's still in one square it's full intensity but spread over three squares would severely dim the light effect.

  • \$\begingroup\$ The way I actually ruled it was as a close blast 3 (since he is scattering the dirt and not just throwing it at one spot) he had to guess where he thought the creature was and use it and make an attack roll if he was in the blast. but the question is about the usage of Light in this manner not so much about how he throws the dirt \$\endgroup\$
    – user10064
    Dec 13, 2013 at 16:27
  • \$\begingroup\$ Edited to reflect (pun intended) \$\endgroup\$
    – CatLord
    Dec 13, 2013 at 17:43

The Light spell only creates one source of light - think of it as a light-bulb, which is also a single source of light. Both the bulb and the spell emit light from themselves, which means from a single point. You can't cut a light-bulb into pieces, so you can't do it to a Light spell. If a Light spell created several light sources, it would be explicitly stated in the spell description, as it would greatly change the usefulness of the spell.

Therefore, on solids, a single item would start glowing when Light is cast on it. Splitting the item would cause the light to come out of one part of the item, I think, since otherwise you'd end up with two sources of light. You could rule this differently if you wanted - using Rule of Cool for these things is a valid choice to make.

  • \$\begingroup\$ Actually, it is much less clear than that. It says "one object", yes, but then the Effect line says that the spell causes "the target to shed bright light", not that it puts a single point of light on the target. This seems to have fallen into the designer's "we don't care about the details" bucket; the "light bulb" versus "glowing object" issue seems to have been left up to DM taste. \$\endgroup\$ Dec 13, 2013 at 16:19
  • 1
    \$\begingroup\$ do you have any references to back this up? I have a problem with comparing it to a light bulb. You can't cut a light bulb without breaking it, if it is more like a torch, then you certainly could cut the torch into 2 smaller torches. \$\endgroup\$
    – user10064
    Dec 13, 2013 at 16:21
  • \$\begingroup\$ @UrsineFavor The light-bulb is used to illustrate how a single source of light acts. Overall, it's your game and if you think it's cool and want to allow it because of that, then that's your call and a good way to rule things \$\endgroup\$
    – Dakeyras
    Dec 13, 2013 at 16:29
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    \$\begingroup\$ -1 because this stuff is defined nowhere in the rules. (It seems to be legitimate extrapolation based on what the rules do say, but it's not necessarily the way it works) \$\endgroup\$ Dec 13, 2013 at 16:41

Agree with @SevenSidedDie (though not so much with how they developed 4E ;-), the decision is yours. However, I would qualify his final statement about the "game not actually caring". While the rulebook doesn't care, your game-world very well might. I would caution you to give a little thought to alternative uses before you make a final ruling for effects like this. For your players to feel like they can problem solve in your world, they'll need you to be consistent, meaning this is the way they'll expect Light to work from now on. This may open the door for maneuvers that may give you balance issues.

For example, casting spells of this type on sand then partitioning out the sand to share the spell effect across the group, or throwing it into the eyes of several creatures, blinding them. I thought of those two uses immediately, and clever players will think of many, many more.

The point is, with the power of a DM, when you make a ruling you're adding a construct to your universe, so don't do it too lightly, and don't just consider your initial mental model of the "physics" behind the spell. Call a 5 minute break, get a Coke, and think a bit about the over-arching game mechanics and how you might abuse the rule you've just created. I don't want you to let fears of future abuse paralyze you, but it's a complex system, and you'll want to think through the consequences of your actions (just like your players do!). Often there are simple, reasonable qualifying details that will allow the player's clever spell use to be effective without causing you headaches down the line.

For instance, if you are concerned this type of use might make Light too powerful, perhaps you need to add that the illumination is severly degraded when split in this way. It's bright enough to reveal someone that it's stuck to, but no longer provides sufficient illumination to be an effective light source.


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