Opposites Interact! (Japanese: マンムー、パチリス！決めろ氷のシャンデリア！！ Mamoswine, Pachirisu! The Ice Chandelier is Chosen!!) is the 18th episode of Pokémon: DP Sinnoh League Victors.
Next day, Dawn trains her Pokémon before the next stage. Cyndaquil's Flame Wheel collides with Mamoswine's Ice Shard, Togekiss protects herself using Safeguard against BubbleBeam, while Pachirisu and Buneary use Super Fang and Bounce, though they dodge. Ash trains his Gible to use Draco Meteor; the meteor does not explode, but is parted in two. They almost land on Piplup, but Togekiss pushes them back to Gible and Ash. Zoey and Nando visit them and Zoey reminds Dawn although she had a great performance, she has more stages to pass. Nando expresses he wants to see well-thought out performances, which should inspire others.
Brock knows that now the judges will pair the opponents, from which Dawn could battle Nando or Zoey. Meanwhile, James, Wobbuffet and Meowth eat lunch and let Jessie know they will support her. Jessie replies she does not need cheering, as she is steps away from victory and reminds them they need to sell stuff. Dawn decided to use Mamoswine and Pachirisu for this stage, which Ash and Brock think it is logical, as the combinations of Ice and Electricity work well. Ursula sees them and comments on Dawn's victory was but pure luck, thinking she couldn't win this fight. Dawn responds that she will win, with or without her bickering. Later, Marian is about to display the battles. Among them, surprisingly, are Dawn and Ursula, who have to battle each other.
James, Meowth and Wobbuffet sell the souvenirs from the Grand Festival, which gets the attention of many, many people, which means much money for Team Rocket. Ursula and Dawn have their battle; Dawn sends Pachirisu and Mamoswine, while Ursula her Gabite and Flareon. Pachirisu starts with Discharge, but Gabite gets hit, and since Gabite is a Ground type Pokémon, the attack has no effect. However, Pachirisu powers Mamoswine up and takes down Gabite on Flareon. Gabite uses Sandstorm, affecting Pachirisu and Mamoswine, so Mamoswine uses AncientPower to stop Sandstorm. However, Flareon's Scary Face causes Mamoswine to be frightened. Pachirisu goes to use Super Fang and Mamoswine Ice Shard, but they get surrounded by Gabite's illusions via Double Team. Flareon's Shadow Ball causes damage to both Dawn's Pokémon.
Dawn encourages her Pokémon to stand up, which Ursula thinks that makes her great to beat Dawn. Flareon uses Shadow Ball, which hits Mamoswine, as Pachirisu evades the attacks. Mamoswine goes to shatter Ice Shard using tusks and Pachirisu runs. Flareon uses Fire Spin, causing Mamoswine's Ice Shard to disappear, while Gabite's Dragon Claw hits Pachirisu. As they battle, James and Meowth sold everything they got. Meowth sees that one card was not sold, which is Jessie taking a pose in her dress. Seeing the battle, they decide to give Jessie support. Flareon uses Fire Spin, which causes Ice Shard to turn to glitter. Dawn soon sees she has not much points left, while Mamoswine and Pachirisu are exhausted.
Mamoswine uses Ice Shard and Pachirisu runs. Gabite uses Dragon Claw and Flareon Fire Spin, but Pachirisu dodges Gabite and hits Flareon. Mamoswine's Ice Shard encircles Pachirisu. This turns to an ice ball and Pachirisu runs, using Discharge to power this Ice Chandelier up. However, Gabite digs and Flareon jumps in to dodge this move; the Ice Chandelier is shattered. Flareon uses Shadow Ball, which wounds Pachirisu. Mamoswine uses Hidden Power, but Gabite and Flareon escape again, while also hitting Mamoswine using Shadow Ball. Gabite uses Dragon Claw, which hits Mamoswine, while Pachirisu jumps in a hole. Flareon's Fire Fang bites Mamoswine, who uses Ice Shard in the holes. Pachirisu uses Discharge, so Mamoswine uses AncientPower on the ground, which causes Pachirisu to jump out in the ice ball.
Pachirisu, powered by Hidden Power, cancels the attacks of Ursula's Pokémon. Mamoswine uses Hidden Power and Pachirisu Discharge. Ursula orders her Pokémon to dodge, but they have been defeated by the previous attack. Dawn wins this tough battle. Nando and Zoey are impressed, while Jessie is shaking, as she did not had her battle yet. Ursula cannot believe she lost, while Dawn expresses she did not thought she could win this one. Dawn says to Ursula she was tough, while Ursula thinks this was luck and wants to see how far will it get her. Ursula says goodbye to Dee-Dee. Jessie, Zoey and Nando advance to next round too. Jessie is annoyed to see James, Meowth and Wobbuffet supported her. They explain to her they sold everything but some cards. She sees those cards are pictures of herself and gets *very* angry. She signs her signature on and tells them it should tempt the people to buy them.
Ash and Brock congratulate Dawn and wish her luck in next battles. Dawn responds they don't need to worry about it.
- In one scene, a Makuhita is seen standing behind its Trainer. It stands much larger than in the games. A similar sized Makuhita also appeared in Pinch Healing!.
- Among the stuff James, Wobbuffet and Meowth were selling is a picture of Moltres, Zapdos and Articuno.
In one scene, the outline separating Ursula's arm and torso is missing.