You cannot target a face-down Spell Card Special Summoned by "Magical Hats".
This card targets 1 face-down monster you control.
If the targeted monster is not on the field when "DNA Checkup" resolves, its effect disappears.
If the targeted monster has multiple Attributes, like "Light and Darkness Dragon" you only refer to the Attribute printed on the card when resolving "DNA Checkup".
Your opponent declares 2 Attributes when the effect resolves, immediately before revealing the monster.
You cannot activate "DNA Checkup" if either player has less than 2 cards left in their Deck.