Ophie
Salingerian Phony
No need to panic, he will respawn tomorrow. Alternatively you can find Gengar in raid battles because he is currently promoted in Shield for the ongoing event.
And Sword too. Both Gigantamax Gengar and Machamp will appear in Max Raid Battles right now, but based on my experiences, the one in your version's Stow-on-Side Stadium battle is more common.
Oh okay so they respawn once a day is that it? Lol sorry for the dumb question.... Will he respawn at any time or a certain time tomorrow? Thank you so much for the tip!! And ugh yes I cant beat him in the raid battle, i literally lose every time lol any advice on which pokemon will beat him?
I'd like to add that Gigantamax Gengar is at Level 60, so I recommend your Pokémon be at least around that level, preferably with at least one other human player in the raid. You can't count on the computer players helping you out to pull through.