The Coronation is a full screen event in The Office, featuring an Aztec-like entitty flashing to a beat, similar to the Headless Rave Girl event. Both of these flashing events are likely Yume Nisshi's response to Yume Nikki's Aztec Rave Monkey event.
How to Get It
The Coronation is found by heading to the top-left door in the bottom half of the third floor on the hospital side of the Office.
Head down to the dark hallway it opens to and break down the door without a handle using the Nail Bat effect to reveal the room inside, which is empty save for a single bed with a hole in it. Interacting with this bed leads to the event, which can be canceled out of at any time.