Nocturnians

The Nocturnians are a species of shadow-like creatures in the EMPATH: The Luckiest Smurf story series that only come out at night. They seek living physical beings like the Smurfs -- preferably the male of the species -- to cling onto and attach themselves physically like a second skin to engage in a mating ritual that usually if not always leaves the host in a state of pregnancy where they carry the child of another Nocturnian. When the pregnancy reaches its full state, the Nocturnian symbiont that mated with the host returns to cling to the host in order to give birth to the child, after which any sign of the pregnancy is nonexistent.

Empath first encountered the Nocturnians when Papa Smurf had problems with sleepwalking that made him tired and then eventually pregnant, only to find out that he was the unwilling host of a Nocturnian. Papa Smurf considered the experience of the Nocturnian mating ritual to be creepy and then embarrassing. Empath himself was captured by a Nocturnian, which imprisoned him within itself and wouldn't let him go until he satisfied the creature's demands. He later developed the shadow suit so he could pose as a Nocturnian that captured a host in order to help the Nocturnians fight their enemy.