Advanced format ruling
Magical Hats

Card effect (current official text)During your opponent's Battle Phase: Choose 2 Spell/Trap Cards from your Deck and 1 monster in your Main Monster Zone. Special Summon them as Normal Monsters (ATK 0/DEF 0) in face-down Defense Position, Set the chosen monster if it is face-up, and shuffle them on the field. The 2 cards chosen from your Deck are destroyed at the end of the Battle Phase, and cannot remain on the field except during this Battle Phase.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.