Hydra heads

[Halcyon]

I believe option one follows the RAW most closely. If you want to modify the rules based on the 'reality' of what a fictional monster could do, well....GM fiat always rules the day.

 

[TimSmith]

Of course the ambiguous wording in the MM alone makes this whole thing debatable. I think it should be painfully obvious just by looking at the plain CR 4 hydra. Five attacks at +6 for 1d10+3 damage just for an AoO seems a bit much. Fighter moves up, takes five whacks, rogue moves up, takes five whacks, hydra acts, five more whacks. No other CR 4 monster is even remotely capable of that sheer amount of damage in one round even if critically hittng. It is bad enough to take one attack from a hydra while moving up when you know you are going to get attack five more times when the hydra acts next. Using option 1 just makes a hydra a practically impossible encounter unless the DM is soft-balling and/or fudging dice.

Therefore you don't rush up to the monster and get taken apart by the fusillade of bites. Instead you must use other tactics to defeat it-missile fire, spells, wait for it to come to you so you can 5 ft step to attack, rogue tumbles to avoid AoO, whatever.

 

[Nail]

Therefore you don't rush up to the monster and get taken apart by the fusillade of bites. Instead you must use other tactics to defeat it-missile fire, spells, wait for it to come to you so you can 5 ft step to attack, rogue tumbles to avoid AoO, whatever.

Exactly.

The "Hydras attacks with all of its head during an AoO" is the appropriate ruling. PC tactics just have to be different than versus orcs.

 

[mvincent]

Note that however this is ruled, it cuts both ways. PC's can shapechange/polymorph into hydras, can animate dead hydras, can charm them, make illusions of them, etc.

I personally use the less powerful option when I DM, but as a player my co-DM used the more powerful option in a recent hydra encounter. I had absolutely no problem with that. Provoking was easily avoided, and the ruling will certainly benefit me later.

 

[Whimsical]

I am going to be running a Cryohydra in the Shackled City very soon. I think I will have each head count as an independent creature for the breath weapons as well. This will give the party a break if they use energy resistance (only 3D6 per head, rather than 21D6) and let me blast some cool ice jets off amongst other heads biting etc.

I agree with you there, even if it's not supported by the rules. Seven saves against seven 3d6 cold attacks is more appropriate for a ~CR 6 encounter than one save vs. 21d6 cold attack.
Here's a couple of threads on this particular encounter in SC...
The Cryohydra a TPK?
Pit of Seven Jaws in Chapter 4

 

[airwalkrr]

So, when the hydra attacks normally, you don't allow it to attack with all of its heads on one target then? What's the maximum number of heads on one target?

A round occurs within the span of six seconds. Let us imagine, for the sake of argument, that you are a barbarian. Now a barbarian can move 80 feet with a full round action. That means each 5 foot movement you make is less than half a second. I seriously do not see less than half a second as ample time for twelve heads to attack a single square. I already believe you are stretching it by letting twelve heads attack a single square in six seconds. To posit it can happen within the span of 0.375 seconds is ludicrous.

 

[Halcyon]

There isn't a 'reality' rule. However, there are lots of rules for magic. Magic doesn't exist in reality either, but it is really useful for explaining lots of phenomena in fantasy games that would not be possible in reailty. Notice that hydras are magical beasts....

Also, there are always ways to explain game mechanics in game. Sure, in a mechanics sense all the heads are attacking the same square, but maybe in game the heads are bitting at him a few at a time as he moves by and comes in range of each of them.

Regardless, magical beasts are magic. I agree that in reality 10 heads could not occupy the same space at the same time, but then again, in reality creatures can't regrow 2 new heads in 6-24 seconds to replace one that was just severed.

 

[airwalkrr]

Therefore you don't rush up to the monster and get taken apart by the fusillade of bites. Instead you must use other tactics to defeat it-missile fire, spells, wait for it to come to you so you can 5 ft step to attack, rogue tumbles to avoid AoO, whatever.

With all due respect, a 4th-level party is not going to have sufficient means to take down something with fast healing 15 by spells and missile fire alone. Best case scenario, let us suppose your party contains a wizard, a ranger, a bard, and a druid. They are all elves so all are proficient with the longbow and have +2 to Dex. The bard is singing to inspire courage. The ranger (Dex 18, mwk bow +2 Str, using Point Blank Shot) attacks at +11 or +9/+9 for 1d8+4 damage. Now, not accounting for critical hits, he deals either 6.375 or 11.25 points of average damage per round. The wizard (Dex 16) happens to be an evoker with four scorching rays and five magic missiles prepared. For the first four rounds, the wizard deals an average of 13.50 points of damage per round and the five rounds after that an average of 7 points of damage per round. The bard (Dex 16, mwk bow) spends his first round starting inspire courage and after that does an average of 3.85 points of damage per round. The druid (Dex 15, Wis 16) casts flaming sphere the first round and produce flame after that. The hydra will take an average of 3.15 points of damage per round from the flaming sphere for the first four rounds and for the four rounds after that 4.125 points of damage per round from produce flame. After that the druid repeats (he has four produce flame and three flaming sphere spells prepared).

In this (relatively) best case scenario, the hydra is going to take 27.9 points of damage the first round (12.9 after fast healing) and 35.875 points of damage (20.875 after fast healing) each round after that. Assuming no party member goes down and no critical hits are confirmed (we will not assume the hydra confirms either), the hydra will fall on the fourth round.

The party was lucky to have encountered the hydra with a little bit of distance so the hydra does not get a full attack on the first round. On the first round, the hydra moves to attack the ranger (AC 19 from Dex and +1 chain shirt and average hit points of 25), dealing an average of 3.4 points of damage. On the second round the ranger 5-foot steps back to avoid an AoO (or five) and the hydra pursues on its turn, this time dealing an average of 17 points of damage. Uh oh. On round three we rinse and repeat and the ranger dies (for the sake of argument we will assume the ranger went before the hydra). So an average party that focuses in dealing damage from range is likely to lose a party member if they fight a hydra. Clearly the hydra is not a creature that you should fight this way.

Unfortunately, the picture is even bleaker if we assume the hydra gets five attacks per opportunuty and the party specializes in melee. The greatsword-wielding fighter (AC 20 from +1 full plate and +1 Dex, average hp of 34) moves to attack his first turn and (yikes!) takes an average of 14.875 points of damage. He'll be quite dead on the second round after the hydra takes a full attack in rounds 1 and 2 unless the cleric gets to him.

The hydra is a tough critter, no doubt. But you simply cannot deal as much damage with ranged attacks as you can with melee (things like flanking, power attack, and sneak attack add up). An AoO is taken for granted when you fight particularly large creatures in melee, but they usually have to have a weakness. A hydra has a low AC, meaning it is very vulnerable in melee, and if the hydra can AoO like a god, then the monster is an overpowering encounter that needs a higher CR (+2 or +3) because it has no weakness. If you attack from range, it can fairly easily out-heal your ranged attack damage unless your party consists of ranged attack power-houses. If you move into melee, it eats you up with AoOs and makes your life that much more unpleasant. Ostensibly WotC play-tested the hydra for 3e and again for 3.5. The hydra actually got MORE powerful between the two, gaining fast healing in the 3.5 conversion. I do not see how WotC could have come to the conclusion that the hydra was too weak if they were using the interpretation that each provocation means a horde of AoOs.

 

[TimSmith]

A round occurs within the span of six seconds. Let us imagine, for the sake of argument, that you are a barbarian. Now a barbarian can move 80 feet with a full round action. That means each 5 foot movement you make is less than half a second. I seriously do not see less than half a second as ample time for twelve heads to attack a single square. I already believe you are stretching it by letting twelve heads attack a single square in six seconds. To posit it can happen within the span of 0.375 seconds is ludicrous.

If it was 12 individuals (perhaps with reach weapons) all attacking the character, would you have the same difficulty in accepting the attacks as being possible? All the AoO aren't really occurring at exactly the same moment, they are merely resolved that way for the sake of manageability. In any case, I imagine the heads as attacking from all different angles-above, below, curving in from the side and snapping around and amongst each other. I certainly don't see each head as taking up a whole 5 foot square.

 

[Stalker0]

There isn't a 'reality' rule. However, there are lots of rules for magic. Magic doesn't exist in reality either, but it is really useful for explaining lots of phenomena in fantasy games that would not be possible in reailty. Notice that hydras are magical beasts....

I fully agree here. Regardless of what interpretation you pick, you shouldn't let "reality" play into it, characters and monsters alike can do things that just couldn't happen in reality.