Kamen Rider Revice S01 E23 Vice Takes Over... Betrayal After All!?

"The hero and the demon are a tag team... in other words, the strongest!"

Following a mishap with the unsanctioned Rolling Vistamp, Ikki and Vice switch corporeal states. Overjoyed by his new state of being, the latter goes rogue to destroy the Vistamp and make the switch permanent.