(Inspired by the incoming Hack & Slash's ecology of the yeti)
When a shaman dream in the mountains, they can dream they are a wild beast and walk the land as a yeti.
If you look in the eye of the yeti you can see who is dreaming (this is scary). But if you do, the dreamer can see their dream-self reflection in your eyes and risk loosing their mind and waking up as a mad man.
Snow elf Sorcerers can create and project themself (or others) into yeti homonculus (or golems).
A yeti with a face twisted by the frozen winds of the mountains.
Maybe a frostbite victim that turned into a yeti or a maybe a very very old yeti.