nail Jell-O to the wall

nail Jell-O to the wall

and nail Jell-O to a cross and nail Jell-O to a tree

phr. to do something that is totally futile. (Jell-O is a protected trade name.) You’re wasting your time. Trying to get him to do that is like nailing Jell-O to the wall.

See also: nail, to, wall

McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.