Terrible Twos at 16 Months?

My son is usually pretty well behaved. Yes, he gets into mischief and acts out sometimes but nothing out of the ordinary for a child his age. HOWEVER, the past few days he has been a MONSTER! Constantly doing things he knows he shouldn't and then laughing about it when he gets in trouble, hitting (in a playful way, he's not angry), taking all his cousin's toys and shoving him if he tries to get back, throwing things, etc. I know this can be normal behavior and if it was just a day of it I wouldn't think anything of it but he has been exhausting for several days now. Even my parents, who think he's an angel, we're making comments yesterday. He is not in a bad mood so I don't think he's teething or getting sick. Is it possible this is the beginning of your terrible twos and if so how am I ever going to survive?!?! 😕