Using the Catapult spell with a flask of alchemist's fire, can you deliver both 3d8 bludgeoning damage as well as the alchemist's fire damage?


3 Answers 3


This is up to the DM

The pedantic answer is that spells and effects only do what they say. This means catapult only deals damage to the flask, not activating its features. You have not taken the action nor made the ranged attack with it that it describes. How many hit points any one object has is also up to the DM, but using the suggested hit points from the DMG (p. 247) a resilient tiny object has 2d4 hit points, so it is reasonable to assume the flask is destroyed. However, the alchemist's fire has no description for what happens when it is destroyed, so it is on the DM.

Your DM might use the base description as a basis for what should happen, and apply the fire damage to the target. Or, they may rule that it does not hit in a sufficiently focused manner to apply harm to the target and so the target does not suffer damage. The main perceivable argument for not allowing this, is not setting a precedent for applying real-world logic to the game rules, which might benefit some characters and their abilities much more than others and/or eat up too much time at the table with arguments. On that note, as will any case of a strategy having ambiguity, ask your DM ahead of using it (possibly outside of game time) on how they would rule, so you know that before using it.

  • 1
    \$\begingroup\$ The sticky liquid would still ignite if the flask is destroyed mechanically/physically (which is the basic English meaning in this context), so a DM would need to do something with that fire. Also, nitpicking, a flask designed to shatter by throwing it at a creature would probably not be a resilient object. \$\endgroup\$ Aug 3, 2021 at 7:22
  • \$\begingroup\$ Further supporting your answer there is this Crawford tweet: twitter.com/JeremyECrawford/status/963501248992260096 \$\endgroup\$
    – RHS
    Aug 3, 2021 at 12:29

Considering the text on alchemist's fire states that the concoction ignites when exposed to air, I'd consider that yes, it'd apply both the catapult spell damage and the fire damage from the substance.

It's expensive and very situational anyway, so it's probably far from overpowered, at least on higher levels (3d8 bludgeoning + 1d4 fire, plus 1d4 fire/round)


I would argue that using catapult on items such as Alchemist's Fire was intended. Note, that the spell description for Catapult points out that on impact both the target AND the object take the damage. There is no mechanical reason for random rock or a chair you could use for the spell, to take that damage, role-play value also is rather lacking and flavor could depend entirely on DM's description instead. But if you consider that in order to damage or other effects of whatever is in the vial to take effect, there has to be enough damage to break the vial. If you think that the combo is too consistent you can buff up the HP of the vials (they need to be beefy to not explode on their own as the PC falls on its ass for example). But also keep in mind that if the target succeed on Dex save then the expensive potion is wasted (as well as the spell slot) so there already exists risk vs reward balancing.

One thing I'd like to try out is to have the catapult damage limited by the HP of the object. So that if you catapult a steel ball(HP of million) you can get full 3d8 but if you catapult a glass vial with, let's say, 5 HP you still roll 3d8 to see if the vial breaks but the damage dealt to the target creature cannot exceed 5

  • \$\begingroup\$ It is too far to say that it is "intended" without specific evidence. It has an effect that the DM can use for the OP's purposes. And the spell already accounts for different damage based on weight. \$\endgroup\$
    – schroeder
    Aug 3, 2021 at 7:15
  • \$\begingroup\$ Welcome Mat Szach! You can find information in the Help section on what makes a good answer. Where possible adding some back-up for the theory is helpful, or if you have play-tested a DM ruling, this can also be helpful at times. If you have an additional question/theory, e.g. the catapuling the steel ball, you can ask that yourself as a question. Here is the link: rpg.stackexchange.com/help \$\endgroup\$
    – Senmurv
    Aug 3, 2021 at 7:38
  • \$\begingroup\$ 1) Damage is based entirely on level of the slot used to cast. Although higher level allows you to catapult heavier objects, a tiny rock will do as much damage as a table yeeted using 5th level slot. "When you cast this spell using a spell slot of 2nd level or higher, the maximum weight of objects that you can target with this spell increases by 5 pounds, and the damage increases by 1d8, for each slot level above 1st." \$\endgroup\$
    – Mat Szach
    Oct 21, 2021 at 10:00
  • \$\begingroup\$ 2) No theory needed, here is the exact wording of the description: "When the object strikes something, the object and what it strikes each take 3d8 bludgeoning damage." There is no mechanic or balance issue that requires the yeeted object to take damage other than purposefully breaking that object. I would argue that breaking the yeeted object is within goal of throwing an alchemical fire at someone. For contrast, Bones of the Earth creates pillars of earth that have specified AC and HP and yes when these smash a creature against a ceiling, only the creature takes damage. \$\endgroup\$
    – Mat Szach
    Oct 21, 2021 at 10:20

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