Mr. Wiggles is one of 4 possible rewards for completing the Orgrimmar/Stormwind Children’s Week quests. He comes from the reward Piglets Collar.
My guide to Children’s week quests can be found here.
Mr Wiggles Talents
Your battle pet will always have their first talent after you obtain them their other talents are opened at levels 2, 4, 10, 15 and 20.