You know what they say: Seven heads are better than one!
Another mythological classic, the hydra is a fun one. I personally have never used it in an adventure. I can't even think of an adventure where I fought one as a player. It's not only a tough challenge for the party, it's an interesting listing in the rule book.
First, the stats:
Hydra (from Cook)
No. App: 1
Move: 120' (40')
Damage: 1d10 per head
A minimum of 5 attacks per round is impressive, especially at 1d10 damage. Couple that with decent range of THACOs, and it can get scary to be too close to this thing.
There is a mention of Sea Hydras, which merely adds to the fun. I'm always for anything to spice up aquatic adventures.
Now, instead of the mythological version that grows more heads when one is destroyed, the BtB version just loses one head for every full 8 points of damage. I suppose this is easier on the bookkeeping, but part of me like the regeneration aspect. Of course, there needs to be an out for the PCs; like Heracles burning the neck stumps, there has to be a way to finally stop the thing.
Lastly, there is this marvelous quote from the end of the listing:
"The DM may wish to create special versions of hydra. Special hydras could have poisonous bites or breathe fire (as a dragon, but with a 5' range and only causing 8 points of damage per head). Such creatures should be placed by the DM to guard special treasures."
It just tickles me to have a passage encouraging the DM to muck about and surprise the players with a homebrewed version of a creature. Keep 'em guessing! That's the ticket!
Now, as to fighting them:
- Their AC and Morale is so-so. Most PCs should be able to hit the thing pretty handily. You might even scare it off.
- Unlike dragons, they don't fly and the have no real ranged attack. Pepper them with arrows. Granted, the poisonous or firebreathing variations add some zest, but both are still melee-based.
- They aren't smart (despite the multiple brains). So some good tactics might fool them or lure them into a trap/ambush.
- Treasure Type B: Not a king's ransom, but a respectable shot at hard coin and maybe even some magic. If the DM took the book's advice and placed a special hydra, then maybe there is special loot, too!