CR 13: Dragon or Hydra?

[Tvtyrant]

Just wondering whether a 12 headed Half-Dragon (white) Pyrohydra or a Young Adult Red Dragon is the better CR 13 battle. Hydra seems to do more damage, red dragon has some minor magic.

[Flickerdart]

The dragon will definitely be more interesting - its spells, breath, movement modes, natural attacks, and general cunning are going to give it a much more varied repertoire of moves than the hydra, which just breathes every round that it can and makes a full attack every round that it can't.

[Chaosvii7]

You could argue that it's all the same, because the Half-Dragon template turns the Hydra into a creature of the Dragon type, so they're both Dragons. :smalltongue:

But realistically, the dragon provides a superior challenge, or at the least provides superior options. A Hydra is more of a monster fit for the party to trophy hunt, while a Dragon is more of a monster that would trophy hunt the party.

[Biffoniacus_Furiou]

A 12-headed pyro or cryo hydra is already CR 13, making it a half-dragon makes it CR 15.

Just a regular 12-headed hydra, not pyro or cryo, with the elite array, in the right environment, probably takes the cake for a CR 13. Give it the feats Snatch, Improved Snatch, and Multisnatch, mostly from the Draconomicon. Put the PCs in a situation where they have to swim underwater through a flooded tunnel/cavern, the water is murky enough to limit visibility. The hydra will come at them from one of the sides as they're passing by, getting both a full attack and multiple AoOs. A successful bite will allow it to grab a medium or smaller creature, and it can hold it at a -10 so the rest of the hydra isn't considered grappled. The rest of the hydra's heads can bite a grabbed opponent as though from outside the grapple, so they don't get any dex/dodge bonuses to AC. Also remember that any PCs who were trying to hold their breath for the swim will be in an extremely bad situation.