Ruby and Sapphire series
Regice was Brandon's fourth and final Pokémon against Ash, battling his Pikachu. Pikachu fired Thunderbolt, which does no damage. Regice retaliated with Blizzard, which blew Pikachu away. Pikachu attacked with Iron Tail and Quick Attack, but Regice negated it with Ice Beam, which froze the field. With the field covered in ice, Regice could move quicker, but Pikachu ended up slipping. Regice attempted to use Focus Punch, but Pikachu used Thunderbolt to paralyze Regice, and then hit it with Iron Tail. Regice used Ice Beam to freeze the stadium more, creating a tomb of ice pillars that trapped Pikachu. With Pikachu immobilized, Regice used Rest. Pikachu used Iron Tail to free itself. Pikachu raced towards Regice, but the latter woke up and fired Ice Beam, this time making a direct hit and freezing Pikachu in an ice pillar.
Ash ordered Thunderbolt, but Pikachu was unable to move. The referee went to declare Pikachu unable to battle, but Pikachu used Thunderbolt to shatter the ice. Regice fired another Focus Punch to send Pikachu bouncing across the ice field. Ash managed to get Pikachu to use two Iron Tails in the row due to the ice. Regice used Ice Beam to trap Pikachu in another icy tomb before using Rest again. Pikachu freed itself with Iron Tail and started charging forward with Volt Tackle. Regice woke up and uses Ice Beam to try to freeze it again, but Pikachu dodged and hit Regice before it can launch another attack, knocking it out, earning Ash the victory.
Diamond and Pearl series
Pikachu's battle against Brandon's Regice was remembered by Ash, who was in dilemma whether to evolve Pikachu into Raichu, or not.
While the heroes went to Snowpoint City, a flashfoward of Brandon's Regice firing Zap Cannon at the Battle Pyramid was shown: as Paul used Lairon to battle Brandon's Regirock, Brandon swapped it with his Regice. Paul's Lairon used Iron Defense, but was quickly defeated by Ice Beam and Zap Cannon. Paul used Ursaring, whose Hammer Arm collided with its Focus Punch. It then fired Zap Cannon to paralyze Ursaring, then Brandon swapped Regice with his Regirock to defeat Ursaring.
While the heroes went to Snowpoint City, a flashfoward of Brandon's Regirock, Regice and Registeel using Hyper Beam to stop Regigigas at the Battle Pyramid was shown: Regice was also used to battle Regigigas: it used Focus Punch to attack it, but was hit by its Hammer Arm. Regice was using Zap Cannon to stop it, but was confused by the Colossal Pokémon's Confuse Ray. It went on a rampage along with Regirock and Registeel. When Hunter J attempted to capture Regigigas, Regice, Regirock and Registeel started to fire Hyper Beam to stop her. They, along with Brandon, were all turned to stone in order to protect it. After J left due to her client cancelling the deal, the Regi's and Brandon were restored by Regigigas and stayed at Snowpoint Temple in order to rebuild it and guard Regigigas.
- Tomoe Hanba (English and Japanese)