The adventure mode is divided into five levels, and each level has 10 stages. The Yeti Zombie appears on level 4 stage 10 (the lightning level) when anda play through adventure mode a saat time (after completing it the first time). anda will only see the Yeti Zombie if anda happen to be looking at the right side of the screen when lightning flashes. When the Yeti Zombie is killed, anda get 2 atau 4 gems ($2000 atau $4000). Whether atau not anda actually see the Yeti Zombie, anda will get the entry in your Almanac and the Achievement.
Yes...I was just playing the regular game (as opposed to the mini-games, etc.) and he showed up in one of the pool scenes. I didn't think he'd ever tunjuk up either, lol...there's a lot I haven't seen yet in the game. And I've been playing for quite awhile. Hope that helps.