Bogmire can make shadow clones of himself and can teleport and can summon a bolt of lightning to summon his shadow clones and gengar Superhuman Physical Characteristics, Darkness and Shadow Manipulation, Intangibility, Can absorb heat to lower temperature by 10 degrees Celsius, Curse Manipulation, Status Effect Inducement, Sleep Manipulation, Mind Manipulation, Soul Manipulation, Poison Manipulation, Healing, Resistance to Poison, Bug, Grass, and Fairy moves, and Immunity to being Poisoned and Earth Manipulation (within limitations), Power Nullification, Aura (Via Dark Pulse), Offensive Illusion Creation (Via Night Shade), Flight, Pseudo-Teleportation | Same but higher. The third eye growth enables Mega Gengar to freely observe beings and events across space-time boundaries and see into alternate dimensions/universes. Mega Gengar are also capable of immobilizing movement by entering into an object's shadows So they are both ghosts so i think Bogmire will win beacuse he can confuse gengar with his shadow clones.