Spells that do not specify that they do damage but state that they affect hit points

Question

I'm relatively new to DnD in general and 5th edition is my first experience with Dungeons and Dragons. I am confused with some spell mechanics.

Spells usually state that they do damage, such as:

Burning Hands (Lv 1)

A creature takes 3d6 fire damage

Ray of Sickness (Lv 1)

On a hit, the target takes 2d8 poison damage

But some spells only dictate that the hit points are affected:

Sleep (Lv 1)

Roll 5d8; the total is how many hit points of creatures this spell can affect.

Color Spray (Lv 1)

Roll 6d10; the total is how many hit points of creatures this spell can effect. [sic]

In this case what would I do? Do I do 5d8 damage if I cast sleep or 6d10 damage if I cast color spray? If so, why on earth would I use any other Level 1 spell as these two would be exponentially better than any other D&D 5e level 1 spells?

Answer 1

Affecting a number of hit points is not the same as dealing damage

"Number of hit points affected" is a patch for old-school "number of hit dice affected" abilities. For example, if you roll your 6d10 and get 20, you can use your color spray on a creature with 20 or fewer HP, or two creatures with a combined total of 20 HP, or whatever. You would not affect a creature with 21 HP.

This is the advantage of damage - if you were to deal 20 damage, the 21 HP creature would still be injured by your spell. Color spray would not do anything.

Answer 2

Those clauses in Sleep and Color Spray determine targets affected, not damage.

Later in each spell description we are told what happens to anyone who falls prey to Sleep or Color Spray.

(Later in the spell description is also detailed exactly what to do with the 5d8 or 6d10 result.)

Answer 3

If you look at Sleep, it states:

Roll 5d8; the total is how many hit points of creatures this spell can affect....each creature affected by this spell falls unconscious...

With the key word "affect" and the lack of a damage type, this indicates that sleep doesn't actually cause harm but rather add a status to enemies that you manage to overpower.

Casters are more than simple ranged damage. A lot of their usefulness comes from their sheer utility from spells like sleep and color spray. Both of these spells allow for the caster to control the battlefield by deciding who to fight and when, turning the tides in your favor by eliminating threats without the need to be powerful enough to kill them immediately.

Answer 4

Sleep and color spray in no way deal damage.

If you roll a 5d8 and get 18 on a group of four kobolds when casting sleep, three of them would fall asleep, because they have 5 health each, and (-5 x3) = (-15) and 18 + (-15) is 3, and a 3 does nothing to the remaining kobold because it has 5 health -- unless it was already hurt for 2 damage or more, then they would fall asleep.

Also, sleep and color spray affect whoever has the lowest current health first.

Starting with the creature that has the lowest current hit points, each creature affected by this spell falls unconscious until the spell ends, the sleeper takes damage ... Subtract each creature’s hit points from the total before moving on to the creature with the next lowest hit points. A creature’s hit points must be equal to or less than the remaining total for that creature to be affected.

Answer 5

I see where the wording confused you, but it helps to remember that D&D 5e is very particular, and will (barring errors) not say the same thing in different ways. Thus, “takes 2d8 poison damage” refers to a creature taking damage, but “is how many hit points of creatures this spell can affect” refers to how many hit points [worth] of creatures this spell affects. (I added 'worth' for clarity, because it's the creatures, not their hit points, being affected.)