I’ll knock your block/head off!
Definition 1 of 1
Pro Tip 1/3Aggressive Tone
This phrase often indicates anger or frustration towards someone, implying a violent reaction. 
He was so mad he said, 'Keep up that noise, and I'll knock your block off!'
Pro Tip 2/3Not Literal
It's not usually meant literally; it's more often used to express annoyance or as a playful warning. 
They chuckled after she teased, 'Touch my cake and I’ll knock your block off!'
Pro Tip 3/3Informal Context
Used in casual, informal situations among friends or peers, and not in professional or formal settings. 
At the pub, Joe grinned and said, 'I’ll knock your block off if you beat me at darts again!'