Infestation 5e [8 Ways To Use The DnD Spell, DM Tips, Rules]

You cause a cloud of mites, fleas, and other parasites to appear momentarily on one creature you can see within range. The target must succeed on a Constitution saving throw, or it takes 1d6 poison damage and moves 5 feet in a random direction if it can move and its speed is at least 5 feet. Roll a d4 for the direction: 1, north; 2, south; 3, east; or 4, west. This movement doesn’t provoke opportunity attacks, and if the direction rolled is blocked, the target doesn’t move.

The spell’s damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).

Casting Time: 1 action
Range: 30 feet
Components: V, S, M (a living flea)
Duration: Instantaneous
School: Conjuration cantrip

Xanathar’s Guide to Everything, pg. 158

Infestation 5e

The bug-flavored cantrip from Xanathar’s Guide to Everything, Infestation packs a powerful roleplaying punch. Unfortunately, Infestation doesn’t pack much of a punch in combat.

So why do most DnD spellcasters skip this cantrip? We’ll get into just what’s wrong with Infestation, as well as a few common rules questions that come up. Plus, we’ll talk about how you can use Infestation effectively in certain scenarios and what DMs can do to make the spell more attractive.

Who Can Cast Infestation in 5e?

The following classes have Infestation on their spell list:

Druid
Sorcerer
Warlock
Wizard

No subclasses get Infestation for free.

What Does Infestation Do in 5e?

Infestation forces a creature within 30 feet to make a Constitution saving throw or take 1d6 (3.5 average) poison damage and be forced 5 feet in a random direction. The caster rolls a d4 to determine which of the cardinal directions the target moves.

Infestation’s damage scales like most damaging cantrips at levels 5, 11, and 17.

From a flavor perspective, Infestation instantly spawns a heap of creepy-crawlies on the target, which, presumably, distract them and cause them to run away in whatever direction they can. These mites, fleas, etc. de-spawn immediately after doing their job.

What Are the Rules for Infestation in 5e?

The rules for Infestation in DnD 5e are as follows:

Being immune to poison damage doesn’t immmunize a creature from Infestation’s forced movement effect. Spells carry out their entire effect on a failed save, even if they don’t cause any damage. Here’s Sage Advice confirmation.
Infestation’s forced movement never provokes opportunity attacks. “Forced movement never triggers opportunity attacks unless a creature is forced to move using their movement, action, or reaction” (PHB 195).

Since Infestation uses neither, and because the spell description clearly says so, Infestation’s forced movement is not eligible for triggering opportunity attacks.

Infestation also won’t trigger Booming Blade, which requires that “the target willingly moves.”
Infestation can potentially break grapple. The rules for moving a grappled condition state that “the condition…ends if an effect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by the Thunderwave spell.” (PHB 290). Jeremy Crawford also confirmed this on Sage Advice.

For Infestation, this means that if the targeted creature is grappling someone and is forced to move out of melee range by the forced movement effect, the grappled condition ends. If the forced movement allows the creature to remain in melee range, Infestation’s forced movement does not break the grappled condition.
“Blocked” means the creature literally cannot move; it does not mean that moving will cause self-harm. A creature can’t occupy the same space as another creature (PHB 191), or an object, wall, etc. If a creature can move into hazardous terrain, and Infestation forces them to, then they move into that terrain and suffer the effects.
Infestation can cause a creature to dismount. “If an effect moves your mount against its will while you’re on it, you must succeed on a DC 10 Dexterity saving throw or fall off the mount, landing prone in a space within 5 feet of it” (PHB 198).

So if a mounted creature targeted by Infestation fails their Constitution save and their Dexterity save, they fall off their mount.
Infestation does not cause the Poisoned condition. Not all spells that deal poison damage cause the Poisoned condition — Infestation is one such spell.

How Do I Use Infestation in 5e?

Here are a few ways to make good use of Infestation during your next Dungeons and Dragons session:

Move targets away from allies/yourself to get away without provoking opportunity attacks. Forcing an enemy out of melee range has the benefit of allowing allies to run away without taking any potshots on the way out via opportunity attacks.

While Infestation’s random directional nature can never guarantee that the target will be forced in the right direction, it’s not a bad thing to attempt in some situations.
Target creatures who are near hazardous terrain. Things like traps, cliff edges, and spells like Spike Growth all come to mind. Remember that the forced movement from Infestation can cause the target to run into dangerous terrain, potentially multiplying its damage by quite a bit.
Break up creatures with Pack Tactics. Pack Tactics is an ability that some creatures have that gives them advantage if they’re next to an ally. Infestation can break up these formations, reducing the offensive formidability of your foes.
Get enemies out from behind cover. Your ranged allies will thank you when you use your bug power to get that bad guy out from behind the wall so that they can more easily snipe him without the bonus AC and Dexterity saving throws afforded by partial cover.
Unblock doorways. If you just need to get past a creature who’s blocking your way, Infestation can be just the ticket. Again, the random directional nature of the spell means you’ll see mixed results with this application.
Prevent ranged attack disadvantage. If you’re ranged ally is side-by-side with a baddie, they’ll have disadvantage on ranged attacks and ranged spell attacks (PHB 195). Infestation can remove this little annoyance with some lucky rolls.
End grapples. Again, Infestation will only end the grapple if the target is forced away from the creature who they’re grappling. But if you don’t have a better option, Infestation can do the trick.
Roleplay potential. Beyond combat, Infestation is just oozing with flavor. Making bugs, critters, and parasites spawn can really freak out a stubborn nobleman or solidify your character as a boggy spellcaster of deathly power.

Is Infestation 5e a Good Spell?

No, Infestation is not a good spell. Constitution is the highest average ability score of creatures in the game’s main monster sourcebooks, with an average modifier of +2. Plus, poison damage is the most common resistance/immunity in the game, with about 1/4 of the DnD 5e’s creatures sporting one.

This combination conspires to make Infestation tie for the least likely-to-land damaging cantrip in the game (Poison Spray has the same two problems).

Beyond that, Infestation’s utility effect is incredibly lackluster. Moving an enemy 5 feet in a random direction certainly can be useful (I hope the above section proves that), but it’s almost never the best thing you could do with your turn.

Infestation 5e DM Tips

It’s no secret that Infestation is universally bashed as a pretty weak cantrip. It’s such a common opinion that many wonder if there’s an issue with tweaking (read, buffing) the spell to make it more attractive for players.

Common Infestation buff ideas include:

Allowing the caster to choose the direction of movement. A solid, no-fuss buff that makes Infestation beautifully suited for ending grapples, unblocking doorways, and increasing your likelihood of forcing an enemy into dangerous terrain.

To me, this seems like the most well-balanced homebrew buff of Infestation — it makes the utility portion of the spell far more powerful and consistent.
Changing the damage type from poison. A simple fix that tackles the fact that 25% of the DnD 5e’s monster will take 0 or reduced damage from Infestation. Changing to necrotic damage is the most common and (I think) fitting choice.
Increasing the forced movement distance. Bumping up the forced movement to 10 feet might be good, but personally, I don’t think it really tackles the main issues with Infestation.
Allowing the forced movement to provoke opportunity attacks. This buff goes too far in my opinion. A cantrip that reliably allows for opportunity attacks every round of combat is far too powerful, especially when 1st-level spells like Dissonant Whispers exist.

Overall, you don’t have to do anything to change Infestation. In a game with 477 spells, some are bound to be weaker than others. Plus, some players enjoy picking suboptimal spells if it fits their character’s story or creates a more challenging experience.

Simple Infestation 5e Spell Text

Infestation: (Conjuration cantrip, 30 feet, V/S/M (a living flea)) Target must succeed on a Constitution saving throw, or it takes 1d6 poison damage and moves 5 feet in a random direction if it can move. Roll a d4 for direction: 1, north; 2, south; 3, east; or 4, west. This movement doesn’t provoke opportunity attacks, and if the direction is blocked, the target doesn’t move. | +1d6 at 5th, 11th, and 17th levels.