Valve has let loose Half-Life 2's headcrab within Two Point Hospital.
Sega's Theme Hospital successor will host the parasite from this weekend, when the whole game will be free to try until 5pm UK time on Monday, 18th March, which is also when second expansion Pebberley Island also arrives.
Purchase the game during this time and you'll get 33 per cent off.
You'll also be able to theme your hospital with gubbins from other Sega franchises, including Endless Universe, Total War and Football Manager.
But it is Valve's license of the iconic Half-Life enemy which is most likely to draw crowds. Insert the usual Half-Life 3 joke here.
"The sufferer's head has been seized by a rare form of parasitic crustacean," the infliction's description reads. "Fortunately a treatment is available that wrenches the creature from the victim, leaving their head healthy and uninfested."