Esther 5:14

5:14 Haman’s wife Zeresh and all his friends said to him, “Have a gallows seventy-five feet high built, and in the morning tell the king that Mordecai should be hanged on it. Then go with the king to the banquet contented.”

It seemed like a good idea to Haman, so he had the gallows built.

Esther 6:13

6:13 Haman then related to his wife Zeresh and to all his friends everything that had happened to him. These wise men, along with his wife Zeresh, said to him, “If indeed this Mordecai before whom you have begun to fall is Jewish, you will not prevail against him. No, you will surely fall before him!”