Question: Does a creature have to actively touch the bead for it to go off? If either an enemy or ally occupy the same 5x5 space as the bead, can they opt to not touch the bead, or does that physical proximity automatically mean they're touching it? (By this thinking, placing the bead in an already-occupied space would mean it automatically detonates.)

The 5' square is more of a space that the individuals are able to block/influence easily, so I'd say a creature could occupy that spot without touching it. However, I'd say if something knocks it prone, they would end up touching it, if that is the intention of the creature causing the prone condition. The caster can at any time end their concentration and make the fireball go off, so having enemies avoid the bead isn't too much of a problem though.

Since touching it allows a creature a DEX save in order to throw it 40 feet, could the caster keep it at their feet to charge it and then throw it at an enemy, so long as they succeed on the save to throw it? This allows it to be aimed to an extent. Combine it with a Ring of Evasion or something similar and you would automatically succeed.

If you’re a sorcerer, you can use careful spell to charge it in your hand for as long as you want and then throw it

If you're a sorcerer you can also double charge it with Extended Spell... 32d6 fire damage at the end of two minutes.

I'm reporting this for being too powerful. Please. We are just humble dice farmers. 

ka

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BOOM

This just sounds like fireball with extra steps

Time stop+ Forecage+ Delayed blast fireball

KA- BOOOOM!!!

Or,

Timestop > spend all 7th and 8th level spell slots on DBF to surround foe > profit 

Quote from Zethras_the_Worldforger >>

Or,

Timestop > spend all 7th and 8th level spell slots on DBF to surround foe > profit 

 Well, when you stop concentrating on the first bead and it damages your target, Time Stop will unfortunately end.

What if I have my Mage Hand hold it to charge it (or throw it)?

or by the time you get a 7th level spell slot, you have at least 11meta magic points, you have 13, then you concentrating on the spell, and deal 14412d6 damage half as much on a successful save. enough to kill a terask with no resistance at least 4 times, yeah your concentrating on a spell for 24 hours but the payoff is legendary!

Quote from lucky_number_8 >>

or by the time you get a 7th level spell slot, you have at least 11meta magic points, you have 13, then you concentrating on the spell, and deal 14412d6 damage half as much on a successful save. enough to kill a terask with no resistance at least 4 times, yeah your concentrating on a spell for 24 hours but the payoff is legendary!

 

Quote from lucky_number_8 >>

or by the time you get a 7th level spell slot, you have at least 11meta magic points, you have 13, then you concentrating on the spell, and deal 14412d6 damage half as much on a successful save. enough to kill a terask with no resistance at least 4 times, yeah your concentrating on a spell for 24 hours but the payoff is legendary!

 

 And by that point, you can fly above the tarrasque while you do it.

With metamagic you can double the duration with a sorcerer point up to 24 hours, so if the previous duration was 12 hours you can double to 24. You can't use more points to stack the doubling up to 24 hours. Since this duration is one minute, the most you can extend the spell to is two minutes, not 24 hours.

Can you use catapult on the bead? 

Can you Counterspell this when it goes off, or do you have to Dispel it beforehand?

Quote from Yselieg >>

Can you Counterspell this when it goes off, or do you have to Dispel it beforehand?

Counterspell is used to interrupt the casting of the spell. If you can see the bead, the spell has already been cast, and you'll need to dispel it.

Wait so if you hold the concentration on it for a full minute the damage will be 22d6?!

So it says the bead glows, but how much? Could it be hidden with fog or illusion? Theoretically could it be a claymore?