Reconstruction of Meh-Teh by Dr. W. Tschernezky
for Ivan T. Anderson's book Abominable Snowmen: Legend Comes to Life
Why are there so many yetis with cone-heads?
It's all because a scalp thought to be from a Yeti was discovered in a Buddhist monastery in Pangboche, Nepal in 1954. It was pointy.
Source: Bigfoot Lunch Club
Hergé knew of it and stuck it on his yeti in Tintin in Tibet:
And that's how the yeti got his pointy head.