Came back with a content that is not
Shedinja so be glad.
S -> S-
I personally love using this guy, he completely shuts down all support variants such as Smeargle, and eliminate vitally important victory factor of the opposing team thanks to its broken ability Shadow Tag. But why do I suggest to demote this Ghost to S-?
In this Gen, I found it harder to utilize this Gengar. While it can trap the likes to Tapu Lele, I always had to anticipate Choice Scarf set which can be devastating if I failed to make the right prediction about mega evolving or not.
Also these are the new (or updated) threats for Mega Gengar that I find in this gen:
* Lunala (Thanks to Shadow Shield, it can take a Shadow Ball assuming Stealth Rock is not up)
* Alolan Muk
* Yvetal (Significantly more viable this Gen due to introduction of Solgaleo and Lunala)
* Zygarde-C (Retarded bulk allows it to take any 2 hits bar Icy Wind)
In addition, what hampers Mega Gengar is its pathetic bulk, which is 2HKOed by uninvested Gyro Ball from Ferrothorn and Forretress. This usually forces Gengar to press Destiny Bond (followed by Taunt) to eliminate threats, while its best niche is to get rid of an important opponent and take down something like Primals or Extreme-Ceus before it faints.
Despite this, I believe that Gengar is still worthy of staying in S tier because these flaws does not reduce its viability as a fantastic trapper with access to Destiny Bond, Taunt, Perish Song, etc. I just thought it is harder to utilize Gengar this gen due to the change of cirtumstances; nevertheless, it is still S_class Mega mon that has undeniable viability.