Definition
When you cannot comprehend what has influenced someone, you are unsure why they are acting unusually.
左右（某人）；导致（某人）行为异常
I have no idea what has gotten into her; she seems so irritable lately.
我不知道她是怎么了，她最近好像很容易生气。
Your behavior has been really strange lately; what has gotten into you?
你最近的行为真的很奇怪，你是怎么了？
He usually loves to joke around, but today he's being so serious; it's curious what has gotten into him.
他通常很爱开玩笑，但今天他却很严肃；真好奇他是怎么了。