My character traded an Amulet of Health for a Necklace of Fireballs. Yet, what I didn't realize when I made this trade is that the necklace of fireballs isn't as great as I thought. At least according to my DM. According to him, since I have to take each pearl off the necklace and throw it at a creature to attack, I first have to roll to hit (or do an athletics check or something) to see how I throw. If I fail this throw, the creature takes no damage. If I succeed, then the creature gets to do its Dex save to see if it takes full or half damage.

My argument is as follows: If I have to roll to hit, and it hits. Well, then its a direct hit. The character cannot dodge something that has already hit it, so it does not get the dex save. Thus, the way I read it, the dex save determines if I threw the pearl near or far from the creature, and there is no need for any kind of roll to hit. Furthermore, if I do a roll to hit and miss, we then have the complication of deciding what happened. The pearl still landed somewhere and blew something up. So how to determine what it hit? Did I hit my friends instead of the enemies? Did I blow up a building on accident? It just seems simpler to rely on the dex save alone. 

Also, I am not aware of any attack, thrown or otherwise, that has both a roll to hit and a dex save. It's always either or. Having an item that requires both seems pretty weak to me. And I wouldn't have made the trade if I knew this going in. 

Now, the DNDbeyond entry for the necklace seems to be on my side, because it says the fireballs instantly go to a point a choose, rather than having to physically throw a bead. However, my DM gave me the necklace from a book he has, and in his entry it certainly states that I have to throw the bead where I want it to go, rather than the necklace just giving me fire bolt spells. 

So we are at a stand off, and I would like some more opinions on this matter. Thank you.

I can see where he's coming from.

Still, you don't do both rolls. It acts as a Fireball on demand, so you act as though you are casting a Fireball (of the appropriate level according to the number of beads that you throw and the item description). You get to pick exactly where the bead(s) go. The bead detonates, and any creatures inside of the blast radius do a Dex save (DC15). Those that succeed take half damage, those that fail take full damage.

There is no to hit roll. I can see why he might think that, and ultimately as DM he gets the final say. So if he insists, then use you have to do both. Still, RAW, it's just the Dex save. It would be a rather sucky item if itnwas only ~40% hit rate that would be implied by having both rolls. It would say if you were required to do a to hit roll (it would say something like, "perform a ranged attack", like the do with spells).

Yeah I don't think you should have to do both but DM has the ultimate say, so... you'd have to bring it up to them sometime and come to an agreement of some kind.

The standard item of Necklace of Fireballs does not require a roll to hit. You simply launch it at a location up to 60 ft away, and then it explodes in a 20 ft radius, and all creatures within that radius need to make the DEX save vs a DC of 15.

Quote from Farling >>

The standard item of Necklace of Fireballs does not require a roll to hit. You simply launch it at a location up to 60 ft away, and then it explodes in a 20 ft radius, and all creatures within that radius need to make the DEX save vs a DC of 15.

 This is the way it’s supposed to work. However since your DM seems to be requiring a to hit roll your argument that a hit should be a direct hit without a save has merit. If you miss then it’s just the save but a hit should be full damage to the target hit and a save for half for everyone in the area centered on that target. In the end we can advise but you have to work this out between you.

First, I'm of the opinion that your DM is wrong but that doesn't make him a jerk. The issue will be easier to resolve if you can go in with a view that you disagree with his ruling rather than he is a bad person.

That said, of course its his game and the DMs ruling is final. Though I think most things are either an attack or a save, requiring both seems unbalanced mechanics wise and necklace of fireballs in particular. If he does want to rule it his way though, maybe you could at least make an argument that you didn't understand his modified mechanic and wouldn't have made the trade had you had full information.

To hit rolls for an AoE spell? Tell your DM to think it through, what happens if you crit? If you roll a 1, where does the fireball go, is it just a regular miss?

And where does the fireball go on a miss? Can you pick up the beads after the fight? They are making it much more complicated than it needs to be.

Xalthu said everything I was thinking.  The man/woman is a genius.

If the Necklace required an attack roll it would say so. Its being nerfed by the DM a little too much.

Also, wow, I just wanted to say that's a bad trade. mostly because a Necklace of Fireballs is, essentially, a consumable item... you get 1d6+3 beads total, and once they're used, they're gone forever. I kind of feel like Necklaces of Fireballs are more meant as a DM tool.. a way to give an enemy access to a powerful AOE spell without requiring them to be a spellcaster, and when the players inevitably defeat them they don't end up with a potent magical item that gives them a half-dozen free casts per day (like a Wand of Fireballs).

An Amulet of Health isn't quite as exciting, but its benefits are permanent and super useful, unless you manage to get equivalent CON on your own.

Yeah, an Necklace of Fireballs is basically a spell scroll that can be used by anyone but can't be scribed into a spellbook.

Yes, being mistaken or incorrect or making a not fully thought out ruling does not make the DM a jerk.

One thing, I noticed in the description of the Necklace of Fireballs is that its wearer can "upcast" the fireball by throwing multiple pulled beads or the whole necklace as one action.  Especially on the multiple bead front, the "realistic" behavior of multiple bead sized objects thrown by a hand is overruled by the description of how a multi bead toss would work mechanically.  The case against the DM can be made pointing out by the DM's logic the multi bead usage described RAW would be impossible.  

Yes, DM's call in the end, but there's nothing wrong with politely pointing out where you feel the actual function of the item in its RAW description challenges what sounds like the DM's rule on the fly.  

As others have pointed out, RAW there is no required attack roll. Even if your DM is houseruling that you have to throw it with an attack roll the idea of a miss resulting in no damage doesn't make sense for an effect that creates a 20' radius explosion. If anything I could see them ruling that a missed roll results in the center of the blast being off by five or ten feet in a random direction but that's not going to stop the bead from exploding and everything in range getting blasted. 

Honestly it sounds like your DM either thinks the item is too powerful and is trying to nerf it or they just didn't read the rules in the first place. 

You throw the bead 'up to 60ft away.' You do not have to throw it at a creature. It goes where you want it to with surprising pinpoint accuracy, and then explodes as a fireball.

The DM is wrong and I don't understand how you can be asked to roll to hit a creature at all - since the bead explodes regardless, and it will hit any creatures within the blast radius.

I HIGHLY suggest you ask the DM to reverse the trade. He's is nerfing the necklace of fireballs HARD. That trade was already bad initially, and now was made even worse because of the DM's ruling.

From what book is the DM's version? That would help frame the situation of the campaign.