Ah, another ancient callback is mentioned. Here's (>>2125685) the page you might be looking for.
Transcript:
DM: Twilight Sparkle? Twilight Sparkle: Think I'll just order my Magma Beast to clean up the last few ninjas. DM: Super. Fluttershy: Um, then I'm going to use Combined Attack. I'll fly in from the front and Angel will attack from behind. DM: Oof. He's not going to like that. He dislikes it so much, in fact, that he uses a close burst reaction power, hitting Angel first… Fluttershy: Oh no! Rainbow Dash: Angel is still a reincarnation of that old imp assassin, right? Applejack: Yep. Rainbow Dash: Proceed. DM: …and then Fluttershy, knocking her down. SFX: (BONK) (beat) Fluttershy: …Diplomacy?