THE FINAL BATTLE
Attack!
Alright, let's not get too crazy.
Lunala strikes first, smacking Tyranitar with a Moonblast. Being part-Dark, that ought to be enough to take him out.
Unfortunately, it doesn't seem like it was particularly close to doing the job. The big guy's still standing, and he doesn't look all that worse for wear. You may have made a mistake.
Tyranitar's response is a vicious Crunch. Both of Lunala's types are weak to Dark, and even if her Shadow Shield were still up, Tyranitar's Choice Band jacks his attack damage up to a bullshit degree.
Lunala drops like a... well, like a batlike alien god-thing, sort of. Tyranitar stands over her, victorious. The sandstorm he created continues to rage, but he's undeterred.
The less powerful option was a bad idea. Your BEST idea would be to hit Tyranitar with everything you've got, and right now, everything you've got means Lopunny's High Jump Kick. Silver lining: with Lunala fainted, the switch doesn't cost your turn.