The planet I have in mind is slightly larger than Mars and is located in the system behind a planet about twice the size of Earth.
The effect being almostThe effect being almost like a solar eclipse that happens daily (If that makes sense).
EDIT: I like a solar eclipsethe idea that happens dailythey are (If that makes sense)not double planets but in separate orbits instead. Would this increase the possibility of the planet, which is the smaller of the two, and is further away from the system's star, having longer nights?