So, if your opponent sacrificed a monster in order to summon a more powerful card, you can put down this Wall of Illusion card, which will force your opponent to return that powerful card to their deck
However, during each of your standby phases, you must pay 100 life points to keep this effect active
Most decks wont run Mimikuyu, but those that do tend to include just 1 copy of the card.
If playing a more "Artifact"-centric Deck, cards like "Shining Angel" and "Nova Summoner" can help get "Artifact" monsters on field, enabling the Xyz Summon of Rank 5s like "Artifact Aegis" (as a strong defense) or "Artifact Beagalltach" (to destroy and Special Summon more "Artifacts")
If you do, discard that many cards from the top of your opponent's deck
Play all the good wolves, werewolves, and tribal support