I have found out there is a word for when someone mixes up metaphors; the mixed-up phrase is called a malaphor. In celebration of this discovery, I thought I would offer up two of my favorite ones, both uttered in all sincerity by an old coworker:
“We’ll burn that bridge when we get to it.” (“We’ll cross that bridge when we get to it” and “Don’t burn too many bridges.”)
“This is the cross I’ll die on.” (“This is my cross to bear” and “This is the hill I die on.”)
If you have any malaphors that you are particularly fond of, please feel free to add them in the comments.