すごいことになる

expression, godan verb (-ru)

go crazy; get out of hand; end up in an extreme state

Describes a situation or thing spiraling into an extreme, chaotic, or uncontrollable state. Often used in casual speech when something becomes wildly different from expected.

• このまま放ほう置ちしたら、すごい事ことになるよ。

  If we leave it like this, it's going to get out of hand.

• 彼かれが来くると、いつもすごい事ことになる。

  Whenever he shows up, things always go crazy.