Chaerina's Gift [Yu-Gi-Oh Duel Monsters] [1]

Chaerina the goddess who gave the cards to the ancient Egyptians where Atem came from, bestowed one final gift within each of the millennium items. The ability to see duel spirits in a human form, and the power to make them take physical form if ever needed.

So you can only imagine Yugi Moto's reaction when he wakes up the day after his battle with Kaiba, to see a girl with white horns straddling his waist.