TOKYO, Sept. 7 -- For three days at the end of August, Tokyo was home to a start-up that seemed destined for either a Netflix documentary or a sociology seminar: a "Scary Person Rental Service."

The premise was unnervingly straightforward. For Euro20,000 (RM575), the company would dispatch a tattooed, scowling man to stand beside you while you confronted life's everyday indignities: a noisy neighbour, a snide colleague, a philandering spouse.

At higher rates, the scary person could remain by your side for up to three hours, provided you covered their train fare if your grievance lay beyond the Tokyo metropolitan area.

The company stressed its boundaries.

"They will not do anything illegal," its website said, adding helpfully, "We do n...