Egg hunt needs you to find the hidden egg thief in wizard peak. There will be two sections with super charge ramps facing each other. Starting from the direction you would naturally come from, charge down the first, cut left into the second ramp, go up the ramp opposite you and jump at the top, landing on the platform out in the distance. Behind the wall of that platform is the egg thief.
All Achievements Video: Egg Hunt at 7:16