In a Pokémon Contest in ORAS I want to use Mega Sharpedo and Mega Lopunny. I was wondering if they have to hold their Mega Stone in order to Mega Evolve when the audience reaches full hearts, or if it just happens wether it's holding one or not.
In order to mega-evolve during a contest and obtain full hearts, the Pokemon must hold its Mega Stone.
Hope I helped!
Yes, they must hold their Mega Stone.
Source: Experience