The official Limited Time Magic Site has this to say about the event:
Prepare yourself for the return of a monster-sized pleasure! Courtesy of a little Limited Time Magic, you can enjoy the reappearance of the Monstrous Eye-Scream Sundae at Magic Kingdom park. Stop by The Plaza Restaurant and Plaza Ice Cream Cone to discover this chilling treat, which comes complete with 2 scoops of mint chip ice cream, hot fudge, whipped cream, cookie horns, a chocolate eye and sprinkles, all inside a crunchy waffle cone. Don't miss your opportunity to scare up some summer fun—dig into this delightful dessert before the offer melts away!