like a ton of bricks

Very heavily, without subtlety. For example, If he doesn't like your work, he'll come down on you like a ton of bricks. This expression, often coupled with come down on (def. 1), replaced the earlier thousand of brick or hundred of brick. The allusion in all these is to the considerable weight of such a load. [Early 1900s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.