| Transforms the caster into an amphibious, many-headed hydra for a brief duration. Its multiple heads strike in all directions. Edible foes slain by the gnashing teeth are instantly devoured, reinvigorating the caster in their reptilian rampage. The caster gains innate armour and increased health, and becomes resistant to poison.
While transformed, any equipped weapons and armour are melded, and wands cannot be evoked. The form's number of heads is fixed upon casting the spell, and increases with power.
- +30% HP
- Poison resistance
- Gain multiple heads, granting you cleaving and increased Unarmed Combat base damage (2 + (3 per head up to 10 heads) + (1.5 for each head after the tenth)
- Immediately devour any edible monster smaller than you upon kill, gaining satiation and healing (amount healed based on monster HD)
- All equipment slots except for rings and amulets meld into the new form
- Size penalizes evasion
- Very short transformation duration (7 turns minimum, rises with spell power)
Hydra Form provides the caster with some rather extreme strengths and weaknesses for its duration. First and foremost, it should be emphasized that entering hydra form drastically reduces the caster's defensive stats: no armour or defensive mutations means that the caster's AC will drop dramatically, and the increase in size will make all but the most nimble and well-trained dodgers into sitting ducks for its duration.
To make up for this, the caster is given a significant boost to HP, a massive increase in damage output (assuming many heads), and a significant amount of healing each time you defeat a monster which leaves an edible corpse. At its best, this amounts to an extraordinarily powerful vampiric-branded Unarmed Combat attack that specializes in taking out large groups of enemies. Also, the cleaving effect is superior to that provided by axes (secondary opponents do not take reduced damage), and unlike with natural hydras, you only make a single attack against your target, allowing Hydra Form to devastate even high-AC opponents. Unfortunately, these factors only come together in niche circumstances.
Getting enough heads for Hydra Form to become truly devastating is difficult. Your initial headcount is based on your spell power, and there are very few spell enhancers for the Transmutations school of magic. You cannot gain heads by having them chopped off by enemy bladed weapons, either.
The pseudo-vampiric cleaving effect is very impressive under the right circumstances (Vaults 5 is very delicious, for example...), but bear in mind that areas without edible corpses suddenly render the powerful healing effect completely useless. Effortlessly plowing through swarms of weak, tasty humanoids may be fun, but attempting to do so against demons or the undead will likely leave you severely injured. On top of that, the healing effect only kicks in once you've killed an opponent; until that point, it does nothing. A string of unlucky misses or an encounter with a powerful, durable unique may get you killed, no matter how delicious your opponent may be.
Finally, bear in mind that the significant damage output of Hydra Form is nearly matched (at least against a single opponent) by the level 5 spell Blade Hands, particularly for characters with high strength and dexterity. This alternative leaves your defenses largely untouched, and is much easier to get up and running in almost all circumstances. It does have the downside of reducing your spell success rates, but this may not be much of an issue if you only planned on punching your opponents for the next dozen turns anyway.