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 Ghost Light is gonna... Snuff my spark and... use my body as a new vessel... For KSI. Chloe...
[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.
Emmet: And, of course, the Screamin' Banshee. Well, good luck.
Evil Ryan:  Tow who and the Screamin' what?