I used it against a Shadow Rider Calyrex and my turn just ended, what happened?
Sounds like they probably had Espeon VMAX benched. Cards that "prevent the effects of attacks", such as Espeon VMAX or Toedscruel ex, will stop Frenzied Gouging from claiming a knockout.
Bumping to show importance.
Bug - Toedscruel's Slime Mold Colony and Pokestop — Pokémon Forums (pokemon.com)
I agree with @nightblitz42 as long as you did not receive the 200 damage.
Bah, wrong window. How do I delete?