学校来日我会炸了你
[xué xiào lái rì wŏ huì zhà le nĭ]
Translated directly this is 'At school one day I will blow you up.' The expression shows hostility or anger in extreme words towards someone else at school in a more metaphorical than literal sense. In reality it's more used to show how the user was bullied by someone or extremely angry with them without actual intent to do harm.