D&D’s sleep spell employs an interesting mechanic that isn’t built in the same fashion as most other spells in 5th Edition. Like many elements of D&D (especially spells), it pulls inspiration from the historical mechanics of prior editions. As a result, this 1st level spell can be hard to parse for new players. Many have gone as far as to say that the mechanic is simply bad. Even D&D Lead Rules Designer Jeremy E. Crawford has suggested that “the sleep spell tech…is deprecated design.”
Without debating the veracity of these opinions, we can acknowledge that perception often overrides reality with game mechanics. Let’s take a look under the hood, check out the balance, and see if we can come up with some recommendations for tweaking the sleep spell in your home game.
Effect. This is a strange one. The sleep spell renders foes unconscious, but not with a simple save mechanic. In fact, there’s no save at all. Instead, you roll up a certain number of dice and start knocking out the weakest characters first, subtracting their hit points from the total of your roll.
Power. The total number of hit points the spell affects is 5d8, increasing 2d8 for each additional spell level. The average number of hit points you’ll affect casting this spell is 27.5. Compare this against the presumed hit points provided by the Dungeon Master’s Guide’s Monster Statistics by Challenge Rating table.
Targets. With a 20 foot radius, there’s a variable number of targets that a spell can effect. Thankfully, the Dungeon Master’s Guide provides an assumption for the number of targets within a spell’s area.
The sleep spell’s 20 foot radius gives us an assumption of four targets. But, remember that targets will be affected in order of ascending hit points remaining. Four just gives us an idea for where to set the cap on the maximum number of presumed targets.
Base Power. An average roll for the sleep spell is not enough to knock out two orcs (CR 1/2). This seems geared towards shutting down smaller swarms of creatures like goblins (CR 1/4) and kobolds (CR 1/8). Now, you might say that the spell was meant to sleep foes who have already been weakened by combat. You’re right, and we’ll get to that in a second.
Scaling. With each additional spell level, you can roll an additional 2d8 to add to the sleep pool. But, that’s only another 9 hit points per level on average, which doesn’t go very far with how quickly monster HP scales.
The sleep spell can quickly become dead weight in a caster’s spellbook. It should not be as strong as an equivalent spell when upcast, but it should maintain usefulness.
No Save. An issue we encounter when trying to scale this spell is that it doesn’t rely on a saving throw. It just works. That’s a pretty terrifying proposition for a DM, and it’s why sleep has a uniquely restrictive implementation. When we expand or rework this mechanic, we need to be cognizant of this fact. Simply adding more dice can quickly make this a powerhouse spell.
Uncertainty. Even where a player has resigned themselves to dinging a target before casting sleep, they never really know whether it’s going to work, not only because of the usual uncertainty of the dice, but also because they have no idea what the target’s remaining hit points might be! Even if your table uses a system like “bloodied” to communicate when a monster has reached half HP, you have no hard information on the actual number of hit points remaining (until it hits zero).
Non-Confrontational Use. Beating someone up defeats the intention to avoid a confrontation by using magic that is ultimately harmless. If I want to incapacitate a pair of guards so my party can sneak by, I don’t want to have to fight. The entire point is avoiding that.
Single vs. Multi-Target. Where sleep excels at putting the kids to bed, it would be nice to have a mode that targets down the threat you want to incapacitate while you deal with the swarm.
There are many ways to tackle this hack, all fraught with their own issues. The thing about the current spell iteration is that it does what it does very nicely. That is, it works on the weakest creatures in a bunch, leaving you to tangle with the healthiest/meatiest ones left over.
If we just scale up the amount of dice we get to roll hit points, we’re risking making the spell a LOT stronger. However, its possible that the issue we’re facing is not with the base amount of dice you roll. The average roll on a level 1 sleep spell is the same as an average HP roll for a bugbear (CR 1). Rather, maybe the scaling is off. The average roll on a level 9 sleep spell is the same as an average HP roll for a Chuul (CR 4). So, the scaling is going out the window somewhere. Perhaps this was intentional in the design, but it makes it scarcely useful to upcast sleep.
We actually get a pretty neat scaling if we just increase the number of upcast dice from +2d8 to +3d8 per level. It matches up nicely with the average rolls for CR 2 and CR 3. The scaling slows down a little bit after that point, matching up our CR 4 example at a 5th level cast, and undershooting our CR 5 example by a bit with a 6th level cast. Upcasts progressively getting relatively weaker against higher CRs is an indication of good balance.
But, are we committed to the mechanic working how it does? Would we sacrifice the current styling to have a system that aligns more closely with other narrative goals we want to accomplish?
One thing the current system does really nicely is that it keeps you from sleep-targeting the main baddie to take them out of the fight. Sleep is really powerful if there’s nobody else around to wake them. With other spells, we rely on things like saving throws to protect stronger creatures. There’s no reason this couldn’t be a saving throw spell.
But, since sleep is so powerful, we can take a page from other spells that induce powerful conditions, such as contagion or flesh to stone, and use a multiple save paradigm. Now, I really hate when you have to make an attack roll to kick a target into saving throws. It’s just too much. But, I don’t mind progressively stronger effects based on successive saves. So, here’s what I came up with:
Thanks to u/Phylea for bringing our attention to Mr. Crawford’s comments on the unique nature of the sleep spell’s design.