The Chaos quest should be stocked with a number of chaotic, randomness-inviting things, such as chameleons and tins of tengu meat.
Eating a chameleon corpse has a chance of conveying intrinsic polymorphitis.
Instead of actually becoming any random monster, chameleons choose any random monster type to display as, but their attacks and stats remain those of a chameleon.
When chameleons polymorph, they retain their same number of hit dice and hitpoints. So while you may be facing a minotaur or an arch-lich, it’s a very fragile one.
Chameleons randomly select a monster of up to (level difficulty + N) when shapechanging, not any monster ever.
Chameleons only transform into monsters close to them.
Remove instances of “bad RNG” contributing to forms of instadeath or a disproportionate bad effect for a RNG decision made mostly or completely independently of the player’s decisions, because they just add randomness or variance to the outcome of the game:
