Midas' Undoing is a phrase that refers to the story of King Midas from Greek mythology. According to the myth, King Midas was granted a wish by the gods that everything he touched would turn to gold. However, this wish soon became a curse as he was unable to eat or drink anything and his daughter was turned into a golden statue. In the end, King Midas realized his mistake and asked the gods to take away his wish, which they did. The crossword solution for this term is GREED, which reflects the moral of the story - that GREED can lead to disastrous consequences.