Is this homebrew spell Levitating Rocks balanced?

Question

The spell is a level 1 spell but can be cast at any level.

Levitating rocks –

Casting Time: 1 action

Components: V, S, M (Rocks)

Duration: Instantaneous

Rocks levitate and are thrown forcefully at the target or targets in a stright line.

The rocks must be free to move and not covered in order to be used. The caster must see the target and there must be a direct line from the rocks levitation height to the target.

The caster allocates the number of stones for each target and rolls once per target a range attack and adds his spellcasting ability and a bonus depending on the spell level. If the rocks hit they deliver D4 bludgening damage times the number of rocks. The rocks must all levitate in the same time (must be next to each other and not constricted by each other). For example rocks must lay in a field and can't be lifted out of a bag one after the other. It would also be impossible to use this magic as a high level in a too small room.

The number of targest is the number of rocks with a maximum of 10 targests. Outside of the range the caster has a disadvantage to hit, on twice the range the rocks lose all their force and drop to the ground.

Lvl 1: up to 3 rocks or total weight of 300g lavitate up to 1m height. +2 for hit (spell ability roll). range: 10m.

Lvl 2: up to 6 rocks or total weight of 1,2kg can lavitate up to 2m. +5 to hit, rocks can travel in a curve, range: 20m.

Lvl 3: maximum of 10 rocks or total weight of 3kg levitate up to 3m. +7 to hit. range: 30m.

Lvl 4: maximum of 12 rocks or total weight of 12kg levitate up to 4m. +10 to hit. Range: 40m.

Lvl 5: maximum of 15 rocks or total weight of 30kg levitate up to 5m. +13 to hit. Range: 50m.

Lvl 6: maximum of 20 rocks or total weight of 40kg levitate up to 6m. +15 to hit. Range: 60m.

Lvl 7: maximum of 30 rocks or total weight of 80kg levitate up to 7m. +17 to hit. Range: 70m.

Lvl 8: maximum of 50 rocks or total weight of 100kg levitate up to 8m. +20 to hit. Range: 80m.

Lvl 9: maximum of 100 rocks or total weight of 200kg levitate up to 9m. +25 to hit. Range: 90m.

Answer 1

First of all

I like the idea of a rock hurling Earthbender...

But

compare your spell to other 1st level spells. Take Magic Missile for example

You create three glowing darts of magical force. Each dart hits a creature of your choice that you can see within range. A dart deals 1d4 + 1 force damage to its target. The darts all strike simultaneously, and you can direct them to hit one creature or several. At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the spell creates one more dart for each slot level above 1st.

or (because your spell requires spell attack rolls) Jim's Magic Missile from Acquisitions Incorporated

You create three [...] darts of magical force. Each dart targets a creature of your choice that you can see within range. Make a ranged spell attack for each missile. On a hit, a missile deals 2d4 force damage to its target. If the attack roll scores a critical hit, the target of that missile takes 5d4 force damage instead of you rolling damage twice for a critical hit. If the attack roll for any missile is a 1, all missiles miss their targets and blow up in your face, dealing 1 force damage per missile to you. At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the spell creates one more dart, [...] for each slot level above 1st.

So both spells create a maximum number of 11 missiles that deal 1d4+1 or 2d4 of force damage each. That's 11d4+11/22d4 (in average 38.5/55...for when all darts hit) of damage as a 9th level spell. Now compare that to your spell at 9th level: 100d4 of bludgeoning damage that pretty much hit automatically due to +25 on the attack roll... that's 100-400 or in average 250 damage... that's insanity.

On the other hand as a 1st level casted with a 1st level slot, you have a spell that works a little bit like a worse Magic Stone which is a Cantrip:

You touch one to three pebbles and imbue them with magic. You or someone else can make a ranged spell attack with one of the pebbles by throwing it or hurling it with a sling. If thrown, a pebble has a range of 60 feet. If someone else attacks with a pebble, that attacker adds your spellcasting ability modifier, not the attacker's, to the attack roll. On a hit, the target takes bludgeoning damage equal to 1d6 + your spellcasting ability modifier. Whether the attack hits or misses, the spell then ends on the stone. If you cast this spell again, the spell ends on any pebbles still affected by your previous casting.

That out of the way...

...start anew and keep those three spells I mentioned above in mind as a guide line.

Short Tip

Don't pump up the restrictions to justify high amounts of damage. Don't underestimate the players' ability to undergo those limitations. Keep limitations simple... and there's one rule about writing rules balancing... the longer the text is the more unbalanced rules tend to be. And your text is about as three times longer than a spell of the same level.

Answer 2

Horribly unbalanced

First, each rock can be a separate attack. Meaning a 1st level Wizard can make 3 attacks per round (at different creatures) which puts it on par with Magic Missile. However, by level 5 (3rd level spell), they max out at ten attacks in a single round. Magic Missile would only have 5 attacks. Also consider that at level 5, most melee classes get a single extra attack. Even a Fighter would max out at 5 (two attacks, action surge for two more, and a possible bonus action attack).

Mind you, the damage is minimal, but sometimes all you need is a single point of damage to break concentration, or knock a foe unconscious.

Also regarding concentration... based off of a few other questions on RPG.SE, the general accepted answer is that each one of those rocks require a magic user to perform a Concentration check (each rock is a different source of damage). So if all the rocks were focused on single creature, one attack roll can create up to 10 separate Concentration checks.

Second, the to-hit bonus breaks bounded accuracy. Plus you're adding on the normal spell casting bonus (an average of +11 to-hit by level 20).

Third, is distance. Converting from meters into feet, the 1st level casting can go ~30 ft; that's fine. But by 4th level of the spell, it's 131 ft; farther than most all other ranged spell attack (most limit at 120 ft). But that's not all as they can still attack beyond that range but at disadvantage (but still with a +10 or more to-hit bonus). At 9th level they can travel just short of 300 ft, or the length of an American football field. Double that with disadvantage. And then add on Spell Sniper and look out!

From a player perspective, I feel this spell could be limited by DM fiat as it only works on free rocks. Not everywhere a player travels will have rocks, let alone up to 100 rocks just sitting around. You did not include Range in the spell description so I don't know how close the rocks need to be, but maybe that's why the attack range is so huge? Or is range how far away the rocks can be also?

Consider, the 5th level spell, Animate Objects. It also maxes out at 10 attacks, but has a much more restrained scope:

• minimal to-hit bonus, but does not include caster bonuses
• minimal damage based on size
• maxes out at 120 ft range

It does have the advantage of one casting working for multiple rounds, but it still requires a 9th level or higher caster, and requires Concentration which limits what is possible on subsequent rounds.

It looks like you tried adapting Animate Objects down to a 1st level spell and it got away from you.

It needs to be pulled way back.

Answer 3

Underpowered at level one, but progression is steep enough to make it OP by lvl 2; also, flat attack bonus has to go.

The main problem I see with your spell is not that it's not balanced, but that it's designed in a significantly different way from PHB spells, so that it doesn't work well within D&D 5e paradigm.

Attack Bonus

First of all, flat bonus to hit is bad. Why is it bad? Because D&D 5e introduced bounded accuracy, which reduced the spread AC could have. In particular, spells based on attack roll are good against two types of targets - low AC (because they are easy to hit even by wizards) and high AC, but also Legendary Resistance or high saves (i.e. those who are hard to hit, but also can just lolnope your save-based spells that hit automatically). Thus, having a flat attack bonus can increase the usability of a spell noticeably, even if it's just +1 - for example, Rod of Pact Keeper gives exactly that for Eldritch Blast, and it is a Rare magic item. And the kind of bonus your spell has... The highest AC a monster can have is only 25; your spell can hit Tarrasque if cast at level nine, even if it is cast by wizard with 4 Int who rolled anything higher than a nat 1! And on a reasonably built character, this spell basically autohits anything a character could encounter at spell level 5 or 6. That's the one of effects that makes Magic Missile have such low scaling damage. Speaking of which...

Damage progression

I get that you probably was trying to balance this with the need to have rocks available and placed so that can levitate unobstructed. But as written - one can get 100 pumice pebbles weighing 1g, spend a turn spreading them out on the floor and then deal full 100d4 damage, because damage is not tied to size or mass of the rock thrown. By the way, that's way too much for level one spell even if mediated by the need to hit (compare level 2 spell scorching ray: cast at level 9 it gives you 20d6 potential damage, i.e. both less min damage and max damage, requiring ten attack rolls even on single target), and as we previously established - the attack bonus basically means that it's hitting automatically. And that's not even accounting for the chance to crit. That happens, in part, because your damage progression is not linear at higher levels - again, something other spells don't do.

Multiple targets

Since this is a ranged attack - it can easily be used to induce concentration checks (or death saves!). That's the second reason Magic Missile has such low per-level damage; and again, at higher levels flat attack bonus again makes this use much more reliable. Yes, you can't make several attacks on one target - but you still can throw your rocks on several spellcasters per turn.

Range

Again, progression runs away fast. By level 4-5, you outrange all other attack spells. Moreover, long-range disadvantage is mitigated by flat attack bonus (do you see the pattern here?).

Other stuff

Your spell does not specify, which class it is designed for. If it is restricted to single class, it might affect balance - for example, if it is for a class that does not have much direct damage spells.

Let's look at other spells' material components. As you can see, unless the spell specifies that the component is expended on cast, it is usually something character found once and, bar plot twists that take away PCs' possessions, will have readily available always. It's very rare that it's something that players would rely on GM to provide, like berries for goodberry. You are trying to do something different here. It's not inherently bad, but it could get away from you - for example, if DM and player will have different opinions on how big of a room you need to fling full 100 rocks around or how fast a player can get a hundred spherical rocks rolling on the floor.

Lastly - usually spells have very simple progression. They take one, rarely two parameters and increase it for the same amount for each level; that keeps progression in check and spell description free of complex tables.

Conclusion

I advise you compare your spell to chromatic orb. This spell also deals damage (3d8, +1d8 per level) on attack roll @ 90ft range; you can choose the damage type, but the spell also requires an expensive gem as a component. It's probably the closest 1st level spell to what you are making. Trading off the gem component for damage types is probably balanced; if you add more features (like splitting attacks on multiple targets or increasing range or maybe giving the caster advantage on attack roll) - compensate by reducing damage.