Definition
When you cannot comprehend what has influenced someone, you are unsure why they are acting unusually.
左右（某人）；導致（某人）行為異常
I have no idea what has gotten into her; she seems so irritable lately.
我不知道她是怎麼了，她最近好像很容易生氣。
Your behavior has been really strange lately; what has gotten into you?
你最近的行為真的很奇怪，你是怎麼了？
He usually loves to joke around, but today he's being so serious; it's curious what has gotten into him.
他通常很愛開玩笑，但今天他卻很嚴肅；真好奇他是怎麼了。