Its purpose is unknown.
The Operator's Doll appears in Entry #18 and Entry #60. It is possible that it is made by Hoody as a warning to Jay that The Operator is near, or made by Proxies (not in MH's context though) as a side effect of being controlled by the Operator.
When Jay finds the doll in Entry #60, he takes it with him, but does not find anything significant on the doll.
- The Doll resembles a "Rathet" which is usually used as a 'Likeness', or a 'Witch Doll' for ritual purposes and Voodoo.