In my setting, there is some sort of cosmic war going on between two factions. This war climaxes in one of the warring sides having the moon of their home-planet being redirected into the home-planet, basically ending all life on the planet. For more information this event takes place around the 26th-century, so very advanced military technology could be utilized here. The moon in question, has a mass of about 3.06603 × 10^25 kg (around 1.9% the mass of its primary), and a radius of 1101.64288125 kilometers (12.5% of the primary's radius).
I want to know a possible way that this moon or similarly-sized astronomical object could be sent on a collision course with its primary as some form of unethical space warfare. Perhaps a high-powered gravity tractor, or a collision between the moon and some other, smaller astronomical object?