fly too close to the sun

To do something especially ambitious and daring that can or ultimately does lead to one's own undoing or downfall. An allusion to the mythical figure Icarus, whose wings made of feathers and wax melted when he flew too close to the sun. He used to be one of the most successful financial advisers on Wall Street, but he kept flying too close to the sun with those high-risk, high-profit investments. Now he's bankrupt. The attorney was determined to put an end to the corruption in the state, but she flew too close to the sun when she opened an investigation into the governor's affairs. That junior executive challenged the CEO in front of the board? Hoo boy, he's flying too close to the sun.