Playin Shining Pearl, had the weirdest battle against Cynthia- everything was going normal, but against Garchomp, I realized that it had Earthquake, D-Claw, and Poison Jab... and I had Bastiodon, Haunter, and Azumarill left. So I decided to PP stall it out, which worked fine, but I ended up losing anyways- I was keeping track of its PP on an online calc, and I knew it had 1 Poison Jab left in the tank, but it was spamming Swords Dance against Bastiodon. Usually, it'd just finish off a move before using useless statuses, but I didn't think much of it, other than that I had to attack with Bastiodon over Haunter (who had D-Gleam) and Azumarill (who had Play Rough). Once it started Struggling, I realized why it did that- keeping a backup Poison Jab essentially forced my into attacking with Bastiodon(whose Heavy Slam wasn't good at all.), and I couldn't use up her Restores or KO Chompy. Bastiodon lived a lot of Struggles due to its defense, Sturdy, and Protect, but Cynthia had an unfair share of Full Restores in her back pocket. Chompy was also faster than my team, so even though it had 0 PP left and was her final mon, 3 Swords Dances is still a lot.
Anyways, if you're going up against her soon, bring something that's faster than 221.