Quote from HammyxHammy >>

The most harmful thing a spell like this does isn't how flagrantly broken it is. It erodes confidence in the game and it's designers. Anyone can look at this and immediately recognize it's OP to the point of not just being minmaxer bait but actively disruptive to play. So why can't WOTC?

Because they suck at balance. This is the company that looked at the Peace and Twilight domain clerics and considered them balanced. They just aren't good at it.

My homebrew: The spell does 4d4 damage + 1d4 for each spell slot level above 4. That keeps the damage basically the same at base level (which is reasonable), makes it much more reasonable when upcast, and is very easy to remember and implement.

Even if you say. about it not being spells. giant scorpion has 3 attacks. which a druid can turn into. if all 3 hit that's 6d8. plus primal strike. the damage scorpions have.

This should only trigger on the first attack you hit on a turn, and maybe a bonus action to activate. Its main intention is as a spell that gives Casters who normally don't make many attacks, to have a hard magic powered hit when needed, not to buff out attack focused builds to infinity or to proc off of multi impact spells like Scorching Ray. Only then could you allow it to scale that well on upcasting. Otherwise, you would need to make it scale like spirit shroud by giving it a d8 every two levels not two d8s every level. But for the sake of having spell variety, and not just a buffed spirit shroud spell, I would go with the single hit big scale option. Or have it conjure actual spirits that get consumed, similar to how minute meteors or crown of stars does it.

my friend, put this spell on a moon druid with a giant scorpion

The old version is better

I don't think this spell works with Magic Missile. As per spell's description, you have to hit with an attack. Magic Missile doesn't make attacks, it just deals damage. 

However, this still works with Scorching Ray or Eldritch Blast, which would lead to comparable levels of insanity. With a 9th Level CME and 8th Level Scorching Ray (9 rays), this would deal (2d6+12d8)x9, or about 549 damage if everything lands (still enough to one-shot any ancient dragon). However, this is assuming everything lands, which is statistically very unlikely. 

This spell is still way too strong. My friends and I playtested this in a high-level one-shot on a valor bard/warlock multiclass and even with trash rolls and suboptimal spell picks (they were fighting the Tarrasque so Eldritch Blast and Scorching Ray didn't work) it still kept pace with our eldritch knight player who literally had the Wand of Orcus piling on 2d12 damage per hit. 

Quote from GwidianofManos >>

A warlock cannot learn this spell without taking enough levels of druid ir wizard to get level 4 spells and there's no feat that allows you to take a level 4 spell from another class. I suppose you could multiclass but the combo would be a nightmare

 There's one other class that gets this spell: the bard. Magical secrets at 10th level let you steal spells from the Wizard spell list, including this one, and bards are much easier to multiclass with warlocks. 10th+ level valor bard (extra attack deluxe for the win) plus two levels of warlock for Pact of the Blade (not required, just quality of life), Eldritch Blast, and Agonizing Blast and you've got yourself a late-game steamroller. 

Guess wizards didn't anticipate the whole nova wizards becoming a thing. Slap some steelwind strike on there and your cooking with some gas. If you want to guarantee damage, spirit guardians is rather nice. 

Quote from WingedWolfAlpha >>

The max average damage you can do with this spell, by upcasting this to level 9, and summoning 10 magic missiles with level 8, would AVERAGE about 565.555 points of damage.

To put this into comparison, the tarrasque has 676 hit points (comparison, the tarrasque reflects missiles to the caster). And being how each missile always hits, you will one-shot ANY of the ancient dragons (gold and red has 546 hit points). Not to mention conjure minor elementals stays, so you can continue casting magic missiles. Wizards of the coast will change this I am sure.

Edit: If they change it, I hope we can have actual elementals again. Now you can no longer summon invisible stalkers. (Though I am a "forever DM" so I wouldn't even be able to)

 Nope. Magic missiles are not attacks (no attack roll is made). So that doesn't work.
Upcast Scorching Ray is probably the best comparison. Still very, very broken.

From useless spell to useless spell 

(You can't use banned spells)

me quietly adding this to my adult dragon stat block in the corner

I would MUCH more prefer if it was just first hit on your turn so you won't need one specific "valor warlock" to max out amount of attack and could use in on any builds.

And it would make is even waker than "upcasting fix". Because linear upcasting would nerf it's damage less than 4 times but one attack would nerf is damage, like, 7 times or even more

WoTC is removing all summoning spells and replacing them with more movable AOE spells similiar to spirit guardians or moonbeam.  I get that they were trying to make encounters simpler to run for DMs, and also summoning spells can be more powerful than they seem since there's more action economy and total hit points on the player's side, but don't remove the idea of the spell instead of fixing it.  At least reduce the amount of creatures you can summon, cause I wonder if a lot of problems with summoning spells came when creatures summoned 8 CR 1/4 creatures (even that has plenty of counters, notably AOE spells or AOE abilities like breath weapons).  

5. Unarmed Strike (I think including its usually non-damaging options of Grapple & Push? Pretty cool.), 6. Druids' WildShape attacks like Bite, Claw, etc., 7. Dragonborns' Breath Weapon Attacks (they use a saving throw, but since this spell's text says 'attack',  not 'attack roll', I'm almost sure this still works), & probably more :) There's so much variety in this game! 

My main problem with this is it makes Fount of Moonlight irrelevant as it's strictly inferior and both bard and druid can get conjure minor elementals.

Making it once per turn would probably fix most of the issues.

I don't think the scaling is too much of an issue if it's once per turn, you are at most getting 2 applications, have to maintain concentration in melee range for the 2nd application and past 6th level there are better things to do with 7th level spell slots. Once per turn also distinguishes this from Fount of Moonlight which has more raw damage but less of a debuff, while Conjure Minor Elementals is a stronger control but smaller damage.

Quote from AxliTabaxiRogue >>

5. Unarmed Strike (I think including its usually non-damaging options of Grapple & Push? Pretty cool.), 6. Druids' WildShape attacks like Bite, Claw, etc., 7. Dragonborns' Breath Weapon Attacks (they use a saving throw, but since this spell's text says 'attack',  not 'attack roll', I'm almost sure this still works), & probably more :) There's so much variety in this game! 

Dragonborn breath weapons are not attacks because they don't use an attack roll.

It does say that you use that ability as part of the Attack action, though, in case you're a Fighter or so with Extra Attack. :) 

Quote from AxliTabaxiRogue >>

It does say that you use that ability as part of the Attack action, though, in case you're a Fighter or so with Extra Attack. :) 

That's true. It's still not an "attack" as the game defines that word, though. 

They fixed it