Is this homebrew spell Acorn Grenades balanced?

Question

I have a character in my game who is having fun imagining himself army crawling around our druid's fog cloud, planting claymores and lobbing grenades. To that end I am looking to create a spell that reflects a bit of that power fantasy.

I tried to balance the spell by looking at Magic Stone and Scorching Ray for inspiration. I would like the damage of the spell to be relevant as a turn-to-turn weapon in a fight at early levels, but really shine as a distraction and trapmaking tool.

Acorn Grenades

2nd-level conjuration

Casting Time: 1 action
Range: Self
Components: V, S, M (an acorn and a bit of peat moss)
Duration: 10 minutes

A magical bandolier of vines grows about your chest with three fist-sized acorns hanging from it. As an action, you can take one of the acorns from the vine and remove its cap, arming it. As part of this action, you may throw the armed acorn at a point within 60 feet, where it explodes. Any creatures within a 5-foot radius of that point must make a Dexterity saving throw. On a failed save, a creature takes 1d12 fire damage, and half as much on a successful save.

If any armed acorns are dropped, hit, crushed, or stepped on, or take any damage, or have not exploded when the duration of the spell ends, they explode, with the same Dexterity saving throw and the same damage as described above. Any acorn that takes fire damage explodes, whether it is armed or not.

When the duration of the spell ends, the bandolier and any unarmed acorns wither and crumble into nothing. You may have only one bandolier and set of acorns at a time. If you cast this spell again while you still have a bandolier or acorns, they crumble into nothing.

At Higher Levels. When this spell is cast using a spell slot of 3rd level or higher, the bandolier grows one additional acorn per slot level above 2nd.

Available on the Druid and Ranger spell list.

Answer 1

Thats a lot of fire damage! But it's probably okay

Some things:

1. The spell doesn't require concentration. Most spells like this do, but yours shouldn't; Not requiring concentration lets the spell be used more often and in a wider variety of combos, and the potential to take 3d12 (or higher if upcast) fire damage yourself if you're careless is a fine balancing mechanism as regards not requiring concentration-- having this spell on all the time is a terrible idea.

2. The acorns as grenades are initially strong, but later weak. 1d12 damage with no ability modifier or anything like that is a lackluster amount of damage for an action past level 5. To make the acorns' damage worthwhile at the pretending-to-be-normal rate of 1 per action, a player needs to catch increasingly large groups of enemies in the 5' blast radius. At level 3, though, the 1d12 with guaranteed half damage is not bad even against single targets

3. Not getting to throw an acorn on the first turn severely weakens the spell-- you can only cast it in cover or out of combat or something where an enemy can't immediately respond with a fire bolt on your completely vulnerable character. Furthermore, the best you'll ever do with the spell the pretending-to-be-normal way is 1d12 per action minus one. That is, your DPR calculation starts with a big '0' and then has to make up the difference from there depending on how long combat runs for.

4. Cleverly plopping the entire bandolier into a group of enemies and blowing it up from afar deals more save-for-half burst damage than just about anything else, consistently through level 7 spells. That's not to say it's better than the higher-level evocation spells-- nothing else with that format hits such a small area and the single target spells like disintegrate do significantly more damage as befits their higher level. But all the way through a 5th level spell slot this spell is very competitive for use.

5. This spell triggers an otherwise unused clause in Glyph of Warding that makes for a pretty intense trap. Because your spell does target a single creature (the caster, in fact) it's eligible to be stored in a spell glyph. Because it creates harmful objects, those "appear as close as possible to the intruder and attack". So, a spell glyph of this spell deals (spell level +1) d12 damage to anyone activating said glyph and those within 5' of them, which is a lot and bypasses the 10 minute time limit on using this spell for traps normally. That's not necessarily a problem-- Glyph of Warding is the best spell in the game anyways-- but it is notable.

6. It's fire damage, so you could theoretically have a chain reaction of these things. A 20th level caster has 3 each of 2nd and 3rd level slots, which is 21d12 fire damage if you spent all that on this spell. That's kind of high-- half a meteor swarm's damage to a single target. You might want to limit the spell to having no more than one such bandolier in existence per caster at a time.

7. It's fire damage so it will often be resisted. That helps balance the otherwise slightly too high damage potential of the spell when used correctly.

8. The spell is weird when used with a druid's Wild Shape. A squirrel or ant hurling explosive acorns 60' or sneaking them inside of some food may be a bit more of a problem than a human doing so. You may want to prevent the spell's use in conjunction with wild shaping into tiny innocuous animals, perhaps by giving the acorns some weight (e.g. 1 lb or 1/2 lb. each).

9. If the spell is too powerful, it's not broken. The spell might need to be bumped up to a higher spell level, but the damage progression and acorns = level + 1 is definitely fine at some point.

You're looking to make a spell that's okay when used without thinking about it too much at low levels but really shines when used in ways that require subterfuge and planning. On those counts, given the above points:

1. Your spell is massively more powerful when used as a trap than as a weapon; its maximal expected single-target DPR goes from \$6.5\times\frac{(n-1)}{n}\$ where \$n\$ is the number of rounds a combat lasts to \$6.5\times(x+1)\times\frac{n}{2}+\frac{1}{4}\times(1+(-1)^{n+1})\$ where \$x\$ is the level of the spell slots used and \$n\$ is as above. This appears to meet your design goal of making the spell better when used correctly than when used like a bludgeon.

2. The maximal expected single-target damage per slot is the highest relative to what the DMG (page 283) says it should be at spell level 2. Its 3d12 has an average damage of 19.5 versus the dmg's 4d6 for multitarget spells with an expected damage of 14. The DMG says a single-target spell should deal 3d10 at that level, which is still 3 points less than your spell's 3d12. Your spell's raw numbers are more in line with a 3rd level spell, where it would still be slightly ahead. Its very small burst area and requirement to either engage in subterfuge and planning or waste 3 actions beyond what a normal spell would require makes this more reasonably placed as a second level spell, however. Also the DMG's numbers are garbage; it says, for example, a 9th level AOE spell is balanced at 14d6 damage, yet Meteor Swarm, the most iconic 9th level AOE spell, deals 40d6 and even CR 6 monsters-- four of which are an 'easy' encounter for a 17th level party-- have an average of 153 hp requiring an average of 44d6 to one-shot them. So you should probably ignore the DMG anyways.

3. The spell may well kill the caster if the caster is unlucky or makes a tactical error. While this does balance some of the spell's bigger upsides-- the lack of concentration for example-- and further the goal of encouraging the caster to play intelligently, it also relies on the DM playing the monsters intelligently and the group being okay with PC death. Furthermore, it's a very all-or-nothing drawback; if it's avoided the spell is super great and if it comes up the spell is super terrible. That may not be ideal depending on your group.

4. Some of the good uses that are too good require the caster to be a Druid or Bard or multi-classed, not a single-classed Ranger. The character you're giving the spell to is a single-classed Ranger. Unless your Druid also makes extensive use of the spell, or a Bard chooses it with their magical secrets ability, the glyph and Wild Shape issues won't come up.

Answer 2

Yes, I believe it is balanced.

Although it does look a little odd for a spell of it's level.

Usually an attack spell like this would have a concentration save to keep it active.

Based on Ice Knife's spell text, you should make few changes based on that. Such as making it a Ranged Spell Attack, and when it hits deal 1d6 bludgeoning damage, or misses it explodes forcing a Dexterity Saving Throw for 2d6 fire damage of things within 15 feet similar to Fire Ball. Although if you are looking to make it more distraction based change it too 5 ft.

Numbers-wise:

Your Spell Acorn Grenades does on average ~6.5 damage while on a successful save it would be ~3 damage on average. It's a bit weak for a grenade so my suggestion of more balancing reflects that. 2d6 would be on average ~7 damage, and on a successful save it would average to about ~3 as well. Although if the intention is more planting of mines you might want to take out the Ranged Spell attack.

Ending thoughts: I believe that would make it bit more balanced, but as it is; It's pretty balanced. Albeit a bit weak.