Stop making me feel a newb!
That's the one! At some point you can upgrade it and spin four (I think) circles right after another, it's awesome. :)
Mega-Gengar was a terrible pain to beat, just as Gengar. I went back to catch Gengar first but that didn't go as easily as planned and even with that it took me so many tries to get past its Mega. I was finally happy to be able to continue and got stuck on the next Mega again, so I gave up and quit with a "There's better things I can do with my life." attitude.
Oh, sounds good! Gym Leaders and legendaries not playing a role in the story and just standing there for no reason awaiting a battle is one of things that really annoy me in the games. It looks like a lack of creativity.
No problem then. I was worried you might have sent it to some random stranger instead.