StagKnight

StagKnight is a black comedy horror film directed by Simon Cathcart and written by Cathcart and Robert Mercer. It was filmed in Effingham, Surrey, England, UK.

A paintballing team known as the Weekend Warriors heads to a woodland retreat just outside London to celebrate the marital engagement of one of their members. However, deep within the forest, an ancient warrior preserved from the time of King Arthur has awoken and begins to hunt them down one by one.

Source: Wikipedia