Mega Gengar has the ability to access other regions and has a vicious nature. Mega Gengar has no interest in opponents unless perceived as prey. Its relationships are warped due to Mega Evolution. It now desires
Zoroark-H is similar to Blacephalon in gen 8, however its access to U-turn pushes it over the edge for me (also the lack of 2AC) meaning it forces progress AND keeps momentum every game, on top of its ability to go mixed and better defensive utility. Gengar doesn't quite compare ...