The <Cleaning Doll> is found in the Elona+ mod of Elona. It is received after completing the basement cleaning quest, which is started by talking to <Lune> the maid chief inside the Maid Mansion on the South Tyris continent.
When used, you will receive the message, "The doll began to move with a mechanical sound. It looks like it was a robot". After this, a Pro-jet will join your party.
The item sprite ID for the Cleaning Doll is 50 (Row 1, Column 17) using the item sprite zero-based position system.