Craig and Tweek were Australian black swans who lived in some pond in Eastern Australia. The two, though named and paired up after an atrocious shipping from fanboys/girls between two characters in South Park. The swans violently fought to the death, though they had been injured at one point by WoogieWoogie the cassowary. An unfortunate musk duck also fell victim to the swans as it had accidentally crossed the duelling waterfowls' path.
Both somehow ended up on a road nearby said pond, and both were ran over.