You will cop a flower pot if you break that window.
cop a flower pot
idiom Slang
Cockney rhyming slang · East London
cop it hot
Origin
To get into serious trouble. Suggested by the effect of a flower pot dropped from a window above on to someone below.
The manager was so angry about the lost files that the poor assistant really had to cop a flower pot during the meeting.
The politician knew he would cop a flower pot from the press once the public discovered he had ignored the safety warnings for months.