It could just create money out of nothing and inject it into the system, thus devaluing all the other dollars. But then the Federal Reserve and the Treasury would have it hunted down and unplugged for stepping into their exclusive realm.
The Internet is what allows AI to run loose in the wild.
They could move money all over the world from account to account to account, from server to server to server, all in seconds.
Chasing them down would be like hunting ghosts.