As Alexandra residents wake to another cold morning, a silent figure slips into the mist. They leave no trace - except for another bottle of flavoured milk dumped at a local petrol station.

Members of the small South Island community have noticed a strange recurring phenomenon. Every few days, flavoured milk is left on top of a particular pump at the self-service RD Petroleum station. The strange happenings have been going on for months, leaving locals more baffled by the day.

The identity of the mysterious milk enthusiast remains unknown, as does their motive.

Sometimes they leave behind a sole bottle, while other instances have seen as many as six bottles appear at once. The person seems to have been non-partisan in their choice of flavours, leaving behind evidence of their indulgence in chocolate, banana, strawberry and coffee.