You haven’t head of me saying this before, but I only say Haunter twice in GL and Gengar once in PCML (This was like the first PCML season, never saw one since)
Basically they pick out all of your counters one by one, before going in for sweep. And in VERY bullshit and inconceiveable ways, too. Never beat one of those teams before.
Meanwhile if I DO use it, I’ll be met with a hard counter and lose.
There was one time where it’s also the first time I met a Shadow Victreebel, I’m running Whiscash Melmetal Cresselia (It’s an old fight) and needless to say I just conceded by the 2nd mon because the way OP plays was outright ridiculous.
(The first mon was a Shadow Victreebel I led with Whiscash, swapped to Cress (PC/FS/MB, old) out of frustration, op stayed a while after sending Haunter. Conceded after Cress blown up 2 of his shields, cannot win.)
(Only recently I’ve actually been properly able of dealing with Shadows in GL)