Jumping on a hydra's back

[juliaromero]

how would you rule a situation where the party rogue wants to try and climb on the back of some big monster they are fighting, like a hydra? If it was a monster without a flexible head on a long neck, would you then make him immune to attacks while he was staying on the back (at least bite and claw attacks)? And how would you rule for him trying to stay on once there?

 

[Mekabar]

Supposed a Hydra's necks are as flexible as a giraffe's, well let me answer with this picture:

Other than that, since the rules don't support such a move, I think it comes down to a grapple.

 

[Starglim]

A hydra is not a good example. Assuming a creature that did fit your description, the big creature would immediately try to throw off its attacker and then attack him on the ground. I agree with Mekabar that this should be resolved as a grapple.

 

[shilsen]

I'd go with a grapple too. There are feats and PrCs which allow one to pull off this kind of maneuver, so it's evidently not intended to be something any untrained (for this specific move) combatant can do.

 

[Pinotage]

Grapple would be the best way to go to mount onto the creature's back, but I'd certainly allow a release of the grapple once you're on the creature's back and then use the Ride skill at -10 penalty for bareback and unfamiliar mount. The DC to 'stay in saddle' would then be 15, including penalties, and 25 for a 'leap' which most mounts would probably do as well.

Pinotage

 

[gnomebarbarian]

Don't forget that something moving into the threatend area of the hydra is going to suffer from attack's of oppurtunity from every single head of the hydra... even if they try to "tumble" in I would make them use a tumble check roll for avoiding each head as the rules state make a spearate check for each opponent under tumble and each of the hydras heads is basicaly another apponent. (they have special rules for hydras if you read up on them) as well it says add +2 to the DC for every enemy after the first. So a 10 headed hydra would take a tumble check of 25 (normal DC for avoiding the attack)+ 18 for "9 extra foes" to avoid the attack of each head. Can you say lunch meat for anyone trying such a move?
Second I would make the person performing such a move use at the least a jump check to see if they can get high enough to land on its back, and a balance check each round with some severe penalties... it would have to be a slipery type surface I would think... (also the PC could be considered flat footed while staying on top of the hydra as per the rule for being attacked while balancing)
Don't forget that the character should only be allowed to use a single attack action against the hydra every round they are "on top" of it. As it should be considred a move action to manuver and stay atop it (especialy if the hydra moves itself) maybe instead of a balance check let them try a ride check with some modifers thrown in if they are trying to "ride" the creature.
Anyway... I would let them try it and not consider it a grapple... they aren't trying to pin the creature or stop it from moving or do any of the other moves that are done with grapples.