Diddly squat informal pronoun
This expression means anything.
I know diddly-squat about her family.
Jane didn't care diddly-squat about what his parents said.
This phrase is a derisive answer to an inappropriate, unreasonable, or stupid question
Whatever you mention, someone will get it.
Used to imply that someone seems to be good, useful, or benevolent but in reality they are not
Don't be fooled by his appearance. He is a devil in disguise.