In Black and White pokedex entries it says:
Black It has been said that they swallow those who get too close and turn them into mummies. They like to eat gold nuggets.
White They pretend to be elaborate coffins to teach lessons to grave robbers. Their bodies are covered in pure gold.
In the anime do you think there will ever be an episode where someone tries to steal a Cofagrigus of someone, or they will start to sell them for quite a lot of money since they are made of gold?