Two-headed bear

Mutated, two-headed bears probably exist, as one is shown on the flag of the New California Republic. A one-headed species of mutant bears known as Yao Guai inhabits the Capital Wasteland.

Appearances in games
The flag of NCR appears in the Fallout 2 end cutscenes. Actual mutated bears, known as Yao Guai are going to appear in Fallout 3.