To "steal someone's thunder" is an expression for taking the credit and praise for something someone else did. That is, someone else does the work, but you take the credit. Ex.: "Brian worked for a whole week on that project, but Dave acted like it was all his doing. You shouldn't go stealing someone else's thunder like that." Dave took credit for Brian's hard work.
In the movie "Percy Jackson & The Olympians: The Lightning Thief," a character steals the thunderbolt of the ancient Greek god, Zeus. While fiction, this would be stealing someone's thunder figuratively and literally.