sorcerer
sorcerer's apprentice a person who having instigated a process is unable to control it.
☞ This is a translation of the French L'Apprenti sorcier, the title of an 1897 symphonic poem by Paul Dukas based on Der Zauberlehrling, a 1797 ballad by Goethe. In this ballad the apprentice's use of magic spells sets in motion a series of events which he cannot control. The part of the apprentice was notably played by Mickey Mouse in the 1940 Walt Disney film Fantasia.