Rival (Diamond & Pearl 113)

Rules

You can play only one Supporter card each turn. When you play this card, put it next to your Active Pokémon. When your turn ends, discard this card.

Reveal the top 5 cards of your deck. Your opponent chooses 3 of those cards. Put those cards into your hand and put other 2 cards on top of your deck. Shuffle your deck afterward.