After a long arduous night adventuring in the depths of a dark and deep dungeon the surviving members of the party gather round what they sense is the final door, behind which is either fabulous treasure or a hideous "boss monster" (see below, steel your girth Cleric, the Wizard and Fighter have your back):
The Cleric pauses, sensing something is wrong, but the moment passes and he steps forwards raising his magical mace (see below, but "facing dangers to the front"):
But when the real danger lies behind you (see below, your fellow characters are not at all what they seemed to be (see below, "evil hisses" give the game away):
Attacked from behind, multiple times at advantage, perhaps casting a "Detect Evil" is a good deep cleanse precaution - something to be done whenever possible (see below, "so ends the Cleric's holy career):
The Dopplegangers come from the new D&D primed resin range Deep Cuts/Pathfinder Battles/Wizkids range. Although I was initially frightened of a 'fragility' I managed to cut away the tiny bits of excess flash and paint them up rather nicely.
Still a nasty DM trick though! The other two PCs could have gone home hours ago ;)