Bad Form
A bad form is any of the transformations the player character can suffer when affected by a beam of polymorph or a weapon of chaos. Beams from other creatures can be resisted with willpower, though zapping yourself with a wand of polymorph always takes effect. Polymorph ignores mutation resistance, but undead players and those already affected by a bad form are immune, and followers of Zin can be protected by their god.
While you cannot cancel a bad form with the End Transformation ability or change form by using a talisman, you can end a form early by quaffing a potion of cancellation.
There are five possible transformations, which are equally likely to happen:
Strategy
Bad forms generally render you nearly helpless. Only tree form can use any weapons or armour; Unarmed Combat specialists have an advantage here, but some forms (like bat form) render even that practically useless. Furthermore, all bad forms except for the tree form outright disable your ability to cast spells. Tree form prevents certain spells from working (for example, it prevents Sublimation of Blood and Translocations like Blink from working). Fortunately, wands still work in all forms.
Players may willingly turn into Tree Form by drinking a potion of lignification. Trees have much higher AC and base UC than all other bad forms; see the potion's page for more details. Most other bad forms, at least in the early game, help you run (Bat / Pig / Wisp) or fight (Fungus).
History
- Prior to 0.20, hostile polymorphs had a small chance to turn the player into a "good" form: Spider Form, Ice Form, Statue Form, Hydra Form, or Dragon Form.
- Porcupine Form was removed in 0.20.
- Most bad forms were added in 0.12. A jelly form was added (eats items, acidic attack but terrible defenses, no item use), but disabled before the branch for testing bad forms was even merged into trunk, let alone a stable release.