TERRAKION JUSTIFY RAISED IT'S ATTACK x 6 (can't go higher x 19). TERRAKION USED ROCK SLIDE
I seriousness, that would be...eh. Seems too cheap to me. There's no real way around it besides using a Steel/Dark/Fighting Pokemon to tank it and pray, or outspeed them and wipe them/try to trim numbers fast, which is kind of annoying in-game, especially from a random encounter.
You know what would be even more extreme? Beat Up being used on a Rattled Granbull in the process of using Rage.