The instant-hire genre of smartphone app took a sinister turn in China this week, when a new one was found to be letting users book mercenaries to hospitalise their enemies for a variable price.

Users were posting ads seeking the services of thugs, mostly retired soldiers, gangsters, crooks and gym coaches, according to the app's description.

A Kunming reporter apparently placed a fake listing on the app and was soon sent the number of a hired thug in Shanghai.

The man promised to be able to put anyone in hospital and operated on an Uber-esque pay structure, which varied according to how much damage the user wanted inflicted (prices ranged between 200 and 500 RMB).

Highly, incredibly, unbelievably illegal, the app was removed from app stores, but according to Qihoo 360 had been downloaded over 40,000 times.

A screen grab from the app

Though it bears an uncanny resemblance to a recent satirical sketch about a thug hire app, the app's producers Changsha Zhang Kong Information Technology Limited has insisted it was never designed for organised illegal activities and instructed staff to remove any listings regarding contract assaults.