(little) tin god
A pompous person. My attraction for him waned after he spent the entire evening acting like a little tin god. Everyone on the school board acts like a tin god. It's so irritating!
tin god
A self-important, dictatorial, petty person who imposes ideas, beliefs, and standards on subordinates. For example, The officials in these small towns often act like tin gods. The tin in this expression alludes to the fact that tin is a base metal with relatively little value. [Late 1800s]