No Guard

No Guard Gengar is extremely strong at forcing out would-be walls that are too passive and thus makes a lot of progress quite easily against teams that are ill-prepared. It can be easily Improofed with some of its true walls that will be mentioned later on.

-cheeseburger15

No Guard Gengar thrives off of Wonder Guards that don't have Magic Coat. The gameplan is fairly simple, once a Wonder Guard switches in use Taunt. Chances are they switch out, in which case you can either Zap Cannon, Moongeist Beam or just OHKO-move if you think an offensive Mon will switch in, or Toxic Spikes if you think a defensive Mon will switch in. This gameplan pretty much guarantees progress against your opponent if they don't have a counter or check listed.

Zap Cannon is chosen as it ruins a lot of offensive Mons as they are unable to kill everything while being incredibly slow. Of course, if you are sure the offensive Mon does not have a sash or if you have hazards up (perhaps Toxic Spikes) you can just click your OHKO against offensive Mons and win.

This Gengar set pairs well with Wonder Guard Arceus as it is Improofed by Arceus quite well.

Despite its strengths No Guard Gengar has a plethora of counters which have only grown in popularity as NG Gengar has become more common. The number one threat to it is Wonder Guards that have Magic Coat. This will completely shut down Gengar. However, this can still be leveraged as you can predict their Magic Coat and switch to another offensive Mon on their now-wasted turn. The most common users of Magic Coat are Meloetta, Audino Mega and other miscellaneous Wonder Guards.

Another counter is Arceus as Gengar is usually Improofed by it meaning it lacks coverage for it. This is unless you run Focus Blast which sacrifices other important matchups.