like a drowned rat
Also, wet as a drowned rat. Soaking wet and utterly bedraggled, as in When she came in out of the rain she looked like a drowned rat. This simile appeared in Latin nearly 2,000 years ago, and in English about the year 1500.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.