Rock eggs event.
you can receive Rock eggs from Professor Bellis to hatch into rock type Pokemon.
Pokemon U can get are:
Aerodactyl, kabuto, Onix and geodude.
Date and time: August 10th at 11pm to August 24th at 10:59pm.
You will get one limited time incubator.
You will have an increased chance to get Rock eggs in event battles.
You must of completed main story chapter 1 the more the merrier in single player normal mode.