Stuck on e4 Agatha and Mega Gengar one-shots all my pokemon (so far). The most information on Mega Gengar I could find was on bulbapedia:

 

Under normal battle conditions in Generation VI, this Pokémon is:

Damaged

normally by:

Flying 1×

Rock 1×

Steel 1×

Fire 1×

Water 1×

Electric 1×

Ice 1×

Dragon 1×

Weak to:

Ground 2×

Ghost 2×

Psychic 2×

Dark 2×

Immune to:

Normal 0×

Fighting 0×

Resistant to:

Poison ¼×

Bug ¼×

Grass ½×

Fairy ½×

Notes:

If Foresight or Odor Sleuth is used by an opponent or the opponent has Scrappy, the effectiveness of Normal-type moves is 1× and the effectiveness of Fighting-type moves is ½×.

 

 

Aside from

https://pokemonrevolution.net/forum/viewtopic.php?t=1466

 

there is not much information on Agatha's Mega Gengar, is there?

Just get a high level poke with sucker punch or a poke that out speeds it and hit it with a STAB move (preferably a super effective one)

Easy get a gyarados dragon dance on the first pokes crunch sweep all mate :) make sure u got hyper potions to use them

Thank you, BadrTheGhost

I used a gengar timid and sweep thur it lvl 95 gengar I leveled up at seafoam island/victory road as a gasley of course and evolve it at lvl 95 to hauter then traded for gengar. Due to when people evolves they become harder to lvl :Smile: .

My lvl 97 gengar OHKO the mega, he's neutral nature iirc (I don't really pay attention to natures and stats lol)

Indeed a good trained Gengar with the right nature should do the job easily! :Exclam:

My Scizor did the trick with a bulletpunch after a swords dance. There are TONS of ways to beat that gengar tbh

I beat all the ghosts with my snorlax and crunch.. so thats also an option if you dont have any of the other pokes

I beat Kanto's E4 with a team of 6 lvl 80ish pokes. Mega-Gengar is no real challenge, you just need to outspeed it. (You need a poke with at least 265 speed)

 

[ I remember because I've been using Alakazam and Crobat back then, Alakazam had 258 speed and wasn't faster, Crobat had 278 speed and OHKO'ed it by using acrobatics + Crit]