Soo, here are some ideas for the polimorpher: (some of them are freshly harvested from a long dead Hungarian pen and paper RPG, but still fine as inspiration)
- claws, fangs and horns (can be a cool boost for a monk fe.)
- 1-2 extra arms - modified arm (for example octopus, cancer...) fun, if lasts for at least some rounds and is always visible.
- acid spit (ranged attack, has to drink something to be able to use it again)
- wandering eye (1 additional wandering eye. Useful by spotting secrets, traps and sneaking people) passive
- double the bones (char has twice as much joints and gets extra dexterity and/or speed)
- tongue of a frog (pulls distant foe to the character) - but can be cut easily
- Chitin skin (for extra defense, but may be unable to wear some kind of armor)
- bone spikes (to use ranged or malee)
- pit mounth (character can swallow up smaller animals or enemies. Can combine with acid spit.)
- stomach pocket (char can eat objects like spikes, metal, everything and vomit them on a foe. Can combine with acid spit for extra damage.)
- (butterfly) wings (bonus to movement and avoiding to be hit)
- mermaid tongue (voice able to charm or hurt everyone! in range)
- moles claws (able to dig without shovel, throw dirt on enemies or dig himself deep to disappear in combat)
What do you think? You have other ideas?