The Sims 2 (2006) for Game Boy Advance:
The Sims 3 (2009):
You can hold a sign with an image of the yeti holding his arms up on it.
The Sims Social (2011):
When you talk to someone, you can choose the action Reveal a Secret and “the abominable snowman” is an option. His angry Gama-Go-esque head appears to represent the secret.