This is how Evil Ryan finds out that it's a prank and showing the film to the mayor goes in Horrificator (CTaRAoMToLaCN).

[Evil Ryan is crawling on the floor to find Chloe]

Evil Ryan: [feeling tired] The Ghostlight is gonna... Snuff my spark and... use my body as a new vessel... For KSI. Chloé...

[He notices Sci-Ryan's amulet]

Evil Ryan: Wait a sec. That's Sci-Ryan's amulet.

Sci-Ryan: [laughs] Got you. Thanks for helpIng Ladybug and Ladyan.

Evil Ryan: Oh gwarsh. I just knew that was a joke the entire time.

Pinkie Pie: You see, Evil Ryan. The only things that we are scared of is your imagination.

Matau T. Monkey: Yup. That and Tow Horrificator.

Ryantinal Prime: And, of course, the Screamin' Banshee. Well, good luck. [transforms to Fire Truck Mode and drives off]

Emmet: I can't wait for the movie. Good luck.

[Everyone wishes each other good luck and

Evil Ryan: [scared] Tow who and the Screamin' what?

[Evil Ryan starts to shake in fear. Meanwhile,