The blind box display is marked with a large standee of a minion dressed as a rooster, holding a golden egg. In front of the standee, a clear case displays all 13 of the possible Minions guests ...

That means your Plant Golems will get bigger and stronger, letting you summon an endless stream of big minions. A new Druid minion, Dreambound Disciple, will make it that much easier to summon ...