D&D 5E I have something... THE TARRASQUE!

[I'm A Banana]

Fly or die again? Sheesh, at least Paizo had the forsight to give their version the ability to fire spines so it had a ranged attack. Even a Fling ogre sized dirt clod or boulder would have been something. Or at least a Leap and Claw to surprise low fliers.

Something to note is that Fly is a concentration spell now. So the best strategy would be to Fly the party, then use ranged attacks, but if the tarrasque decided to chase down and chomp on the wizard, then everyone falls to the ground. So there is a pretty significant Achilles' heel to this strategy in 5e -- chomp the mage.

It's also possibly important that this doesn't seem to be the whole thing (unless our info about the amount of flavor text in the MM is hugely incorrect), and the terrasque is legendary, so there's possibly a lair that might make flying and plinking less of an attractive strategy (and that might even restore some regeneration!).

I'll do you one better. Assuming you can get enough magic bows - or enough castings of Magic Weapon - a horde of 100 skeletons from a 20th-level Necromancer can drop him in 9 rounds. He can kill just 3 of the enemy skeletons per round.

This is less likely to work than the "death by a stinging bee" strategy for two RAW reasons.

The first is action economy -- animate dead gives you a bonus action on your turns to command the creature, but it's still just one bonus action for to command one creature, so only one skeleton can attack in each round. To get 100 skeletons to all attack at once, you're going to need an army of 100 necromancers...which feels a bit more plausible.

The second is Concentration. Presuming that magic items remain rare as the RAW presumes, you won't get 100 magic bows anywhere, and the magic weapon spell is a Concentration spell, which means you can only have one up at a time.

So your 20th level necromancer could totally have one skeleton with magic weapon try and hit the tarrasque (in addition to whatever other actions he wants to do on his turn), but you would need a small army of necromancers (of at least 5th level) to command all 100 skeletons to strike with magic weapons. Pretty inefficient compared to having half of them cast Fly and fire crossbows while the other half concentrates on a Magic Weapon spell.

 

[MonsterEnvy]

It's also possibly important that this doesn't seem to be the whole thing (unless our info about the amount of flavor text in the MM is hugely incorrect), and the terrasque is legendary, so there's possibly a lair that might make flying and plinking less of an attractive strategy (and that might even restore some regeneration!).

The Terrasque is notable for having a connection to the earth. What if they did it so that the entire planet counted as it's lair.

 

[Pillsy]

All I can say is that the mental image of the tarrasque snapping a flying wizard out of the air like a dog with a frisbee has brightened my day immeasurably.

 

[Obryn]

The first is action economy -- animate dead gives you a bonus action on your turns to command the creature, but it's still just one bonus action for to command one creature, so only one skeleton can attack in each round. To get 100 skeletons to all attack at once, you're going to need an army of 100 necromancers...which feels a bit more plausible.

I believe it's one bonus action to command all your skelly bros, not just one.

 

[Mouseferatu]

The first is action economy -- animate dead gives you a bonus action on your turns to command the creature, but it's still just one bonus action for to command one creature, so only one skeleton can attack in each round. To get 100 skeletons to all attack at once, you're going to need an army of 100 necromancers...which feels a bit more plausible.

The rest works, but I think there's a flaw here. The spell says you can command them round-by-round, or give them general, simple instructions like "Guard this area."

I think "Kill that big honking thing with the castle stuck in its teeth" qualifies.

 

[MonsterEnvy]

I believe it's one bonus action to command all your skelly bros, not just one.

But it has to be the same action and you still can't cast magic weapon on all of them.

 

[I'm A Banana]

I believe it's one bonus action to command all your skelly bros, not just one.

Yeah, totally right, missed that. So you could command 100 attack rolls at once, though only one of them could do damage to the tarrasque thanks to Magic Weapon's concentration (and there's nothing in the RAW prohibiting you from finding 100 magic bows that we've seen yet, but I don't think that's...realistic...given 5e's assumptions).

Cheaper, now. 100 3rd-level spellcasters + 1 20th - level necromancer to do 100 magic weapon attacks/round, but still seems kind of like army territory.

The rest works, but I think there's a flaw here. The spell says you can command them round-by-round, or give them general, simple instructions like "Guard this area."

I think "Kill that big honking thing with the castle stuck in its teeth" qualifies.

Sure! The tighter limitation is that with Magic Weapon being a Concentration spell, unless you have 1 mage per skeleton, you're only going to be able to hit with one of those. Big T is going to have a lot of time to break skeletons that can't do doodly-squat to it before one manages to roll a 20.

All I can say is that the mental image of the tarrasque snapping a flying wizard out of the air like a dog with a frisbee has brightened my day immeasurably.

...and all the rest of the party going "Oooooooh shiiiiiii-" as they fall from the sky....

The best bet, assuming that there's nothing negating flight, is to fly an archer fighter or archer ranger, and send 'em 150 ft. in the air above Big T's goofy-lookin' noggin. They'll hit T on a 11+ (assuming a magic weapon of +1), and be well out of the reach of most of the attacks. The rest of the party can run distraction/protection on the wizard, who would be best to hide somewhere dark and protected (possibly fly themselves, and just spend their whole movement going directly up until they can't breathe anymore). Ideally, you do this before you get in a fight with Big T so you can have your flight up and yourself well into the stratosphere by the time he shows up on the scene.

So at 150', your archer(s) plunk away while your mage is at some bar in another hemisphere drinking a fine wine and Concentrating. The T's only chance here is to jump up and grab the archer in its jaws, which might not be easy, and definitely enters DM adjudication territory. Seems like a pretty winning "out with a whimper" strategy, unless there's some lair action going on.

 

[Obryn]

you still can't cast magic weapon on all of them.

Sure, and I said that the first time around.

Of course if you're taking on the tarrasque, it's funny if "get a bunch of magic bows or a huge number of magic arrows, and some 3rd level casters to magic up some weapons" is the only roadblock, is all. Dragons don't stand a chance!

For the record, too, Necromancer Bob can have his full complement of spells, if he times it right. Or a hundred more skelly bros should be need them.

 

[MonsterEnvy]

Sure, and I said that the first time around.

Of course if you're taking on the tarrasque, it's funny if "get a bunch of magic bows or a huge number of magic arrows, and some 3rd level casters to magic up some weapons" is the only roadblock, is all. Dragons don't stand a chance!

For the record, too, Necromancer Bob can have his full complement of spells, if he times it right. Or a hundred more skelly bros should be need them.

Still I don't expect the Skells to be that useful at all times. Going into the lair of the Dragon is going to hard for the Skellys.

I also expect errata will come in that limits the casting of animate dead.

 

[xopher]

64 first-level clerics can do it

So I was pondering how Bounded Accuracy would affect this... in particular, I was wondering how the PCs from the Starter Set would fare against the Beastie...

First of all, all the non-magic guys are useless (except as a distraction). The Wizard is nearly useless, as only Shocking Grasp will work, and he only hits on a 20 (which does crit, but still does little damage).

Clerics, on the other hand have two options... Sacred Flame works, as does Inflict Wounds. Inflict Wounds does slightly better average damage (again, only hitting on a 20, but doing 6d10 because of the crit), but Sacred Flame is easier to use (60' range and unlimited castings).

The Beastie gets advantage on saves, but it still fails the DC 13 save 36% of the time (because of its sucky Dex save). On average, the Clerics will do 1.62 HP per Sacred Flame. Even with the the three free saves, the Beastie will go down after 421 Sacred Flames (on average).

Since the Beastie can move 140' per round, the best chance the Clerics have is to start out being chased. Assume the Clerics arrange themselves ranks 140' wide (28 Clerics), to allow maximum coverage of the 60' spell range (including the 40' width of the Beastie). The Clerics should arrange to let the Beastie close to 60' (they can adjust the encounter range by not moving their full 50' Dash as the Beastie closes, as long as they start at least 200' away). If your DM uses square-fireballs grids, this is a 28-wide line. If you instead use 1.5' diagonals, this is a 28-wide curve...

Once the Beastie closes to 60', the last rank gets 28 Sacred Flames off as the Beastie uses its three Legendary Actions to close the remaining 60'. On its turn, it (probably) kills five Clerics, then three more with Legendary attacks as the Clerics do their actions (these guys do not get their spells off, since the Beastie can choose to kill ones that haven't had their action yet).

After the first round, everyone else is within 60' and can Sacred Flame at will. No one moves out of range (no AoO's) and the Beastie kills 7.6 Clerics every round while the remaining guys nuke him. Note that since Sacred Flame ignores Cover, it doesn't matter that the Clerics have to cast from the back ranks. Also note that the Fearful Presence doesn't affect anything either -- fear causes disadvantage on attack rolls (Sacred Flame has a save, not an attack roll) and fear only prevents moving closer; it doesn't make you run away.

Stuffing this into Excel, it looks to me like 64 Clerics on average can take him out. Two survive on average. They get 2,422 XP each, enough to get them almost but not quite to 4th level.

Of course, to make sure, you'd want more safety factor, but on average 64 will do it.