A silvery beam of pale light shines down in a 5-foot-radius, 40-foot-high cylinder centered on a point within range. Until the spell ends, dim light fills the cylinder.

When a creature enters the spell’s area for the first time on a turn or starts its turn there, it is engulfed in ghostly flames that cause searing pain, and it must make a Constitution saving throw. It takes 2d10 radiant damage on a failed save, or half as much damage on a successful one.

A shapechanger makes its saving throw with disadvantage. If it fails, it also instantly reverts to its original form and can’t assume a different form until it leaves the spell’s light.

On each of your turns after you cast this spell, you can use an action to move the beam up to 60 feet in any direction.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d10 for each slot level above 2nd.

My Comments: Moonbeam: Or, Why Wording is Important.

This can be a great spell- when used correctly. But along with the wording of several spells in the Handy Dandy Player’s Handbook, this one is… vague. I admit that as a DM I’ve made improper rulings as to what this spell can actually do, so let’s take a look at the details to see how this spell works.

The main issue with the wording revolves around the word “enters”. We see the line from the spell description:

“When a creature enters the spell’s area for the first time on a turn or starts its turn there…”

What does it mean to “enter” a spell’s area? Just when the creature comes into contact with the area of effect? If that’s so, each round after you cast, you could just take the Moonbeam and wiggle it all over the battlefield, causing a wake of Constitution saving throws and radiant damage. That seems remarkably overpowered for a second-level spell!

Luckily, our Main Man Jeremy Crawford has provided us with some clarification of what “entering a spell’s area” actually means, in the Sage Advice Compendium.

“A creature enters the area of effect when the creature passes into it. Creating the area of effect on the creature or moving it onto the creature doesn’t count. If the creature is still in the area at the start of its turn, it is subjected to the area’s effect.”

So the creature has to specifically use movement in order to come under the influence of the effect. There are other spells that have the caveat that the creature cannot be harmed if the AoE is simply moved over it. Blade Barrier, Sleet Storm, and Spirit Guardians all specify that the damage is taken when the creature enters the AoE or when it starts its turn there.

This movement doesn’t have to be voluntary, as Crawford goes on to explain that you could shove a creature in with another spell like Thunderwave. The Telekinetic feat also has a bonus action feature to shove a creature up to 10ft away, and the paladin’s Thunderous Smite can also move an opponent on a hit. And of course, a character could also use their action to attempt to just shove the enemy into the Moonbeam, although if they’re in melee, they likely have other actions that would make more sense. You know, like their greataxe.

The other way this spell can deal damage is when the creature starts their turn in the area of effect. So the druid moves the beam onto a goblin at initiative count 15. At the start of the goblin’s turn, on initiate count 11, it will take some damage. It will likely move out of the Moonbeam after that, removing them from the AoE effect.

Unfortunately, this spell can deal friendly fire. The spell doesn’t allow you to pick and choose who is harmed by it. Which to me diminishes the usefulness. I was thinking a good way to use this would be to block a chokehold- a doorway, the entrance to a cave, a hallway. That would require the enemies to move through it to reach you, taking the damage, or just take ranged shots through it. It also requires your companions to move through it to reach the enemies, etc. etc. And unless the enemies are keenly motivated (or stupid) this is likely to just turn into a big waiting game.

The bit about shapechangers doesn’t seem to have any strategic value other than forcing the shapechanger to use their action to revert back to their changed form when they leave the light. This could be useful to help you figure out if that werewolf is actually the mayor of the town you’re visiting, but other than that? Not so sure how this feature would be useful. Feel free to shout at me in the comments if you’ve come across a situation where this feature has come in handy, I am genuinely curious!

Now, if you’re playing a Circle of Stars druid, your subclass has a feature that can be used to great effect in combination with Moonbeam.

The feature is called “Starry Form”, which is a use of wild shape to grant certain benefits. Two of those are particularly good in combo with Moonbeam, as they activate on bonus actions. These are the Archer and the Dragon.

The form of the Archer is as follows:

“A constellation of an archer appears on you. When you activate this form, and as a bonus action on your subsequent turns while it lasts, you can make a ranged spell attack, hurling a luminous arrow that targets one creature within 60 feet of you. On a hit, the attack deals radiant damage equal to 1d8 + your Wisdom modifier.”

After activating this form and casting the spell, on each subsequent turn, your action would be used to move the Moonbeam, picking another target for its start-of-turn radiant damage. And then for your bonus action, you can take a ranged spell attack that does more radiant damage! Radiant damage for everyone! That’s essentially two attacks on a turn, which for a druid is not common.

Now, because Moonbeam is concentration, the other useful form is the Dragon:

“A constellation of a wise dragon appears on you. When you make an Intelligence or a Wisdom check or a Constitution saving throw to maintain concentration on a spell, you can treat a roll of 9 or lower on the d20 as a 10.”

First of all, I love that specifically the constellation is of a wise dragon. No goofy looking dragons here!

But with this, if you take damage while concentrating on this spell, the lowest your save can ever be is ten. Now, the rules for maintaining concentration after taking damage is that “the DC equals 10 or half the damage you take, whichever number is higher.” Unless your enemy is dealing critical hits on the regular or slinging fireballs, the DC is likely to stay either at a ten or be in the very low teens. So having the lowest you could ever roll with no modifiers be a ten is not too shabby at all.

So, should this spell be regularly prepared by your druid? I’d say yes, honestly, especially if you know you’re going to be taking down a pack of wererats or zombies, or if you know the battlefield will have chokeholds that the enemy will have to go through. So go forth and deal radiant damage, and let me know your thoughts in the comments!